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1. Microwave Diagnostics of Dynamic Processes and Oscillations in Groups of Solar Coronal Magnetic Loops

Author

S. Urpo, Maxim L. Khodachenko, Helmut O. Rucker, A. G. Kislyakov, and V. V. Zaitsev

Subjects
Physics, Astron, Solar flare, Space and Planetary Science, Equivalent circuit, Astronomy and Astrophysics, Coronal loop, Astrophysics, Electron, Electric current, Microwave, Magnetic field
Abstract

Low-frequency (LF) modulations of the solar microwave radiation (37 GHz) recorded at the Metsahovi Radio Observatory, are analyzed. Since the intensity of solar microwave radiation, produced by the electron gyrosynchrotron mechanism, is dependent on a value of the background magnetic field [Dulk, G. A.: 1985, Ann. Rev. Astron. Astrophys. 23, 169–224], slow variations of the magnetic field associated with disturbances of the electric current in a radiating source, can modulate the intensity of the microwave radiation. The observed multi-track features of the LF spectra are interpreted as a signature of a complex multi-loop structure of the radiating source. Application of the equivalent electric circuit models of interacting loops allows to explain and reproduce the main dynamical features of the observed LF modulation dynamic spectra.

Published
2006
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2. On the Possible Connection between Photospheric 5-Min Oscillation and Solar Flare Microwave Emission

Author

A. V. Stepanov, S. Urpo, V. V. Zaitsev, and A. G. Kislyakov

Subjects
Physics, Sunspot, Photosphere, Solar flare, Oscillation, Astrophysics::High Energy Astrophysical Phenomena, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Spectral line, Intensity (physics), Radio telescope, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Microwave
Abstract

Dynamic spectra of low-frequency modulation of microwave emission from solar flares are obtained. Data of 15 bursts observed in 1989-2000 with Metsahovi radio telescope at 37 GHz have been used. During 13 bursts a 5-min modulation of the microwave emission intensity was detected with the frequency of νI = 3.2 ± 0.24 (1σ ) mHz. Five bursts revealed a 5-min wave superimposed on a ∼1 Hz, linear frequency modulated signal generated, presumably, by coronal magnetic loop, this wave frequency is νfm = 3.38 ± 0.37 (1σ ) mHz. Both intensity and frequency modulations detected are in good agreement with the data on 5-min global oscillations of photosphere and with the data on the umbral velocity oscillations observed in the vicinity of sunspots. Possible role of p-mode photospheric oscillations in modulation of microwave burst emission is discussed.

Published
2006
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3. Low-frequency modulations in the solar microwave radiation as a possible indicator of inductive interaction of coronal magnetic loops

Author

Maxim L. Khodachenko, Helmut O. Rucker, A. G. Kislyakov, S. Urpo, and V. V. Zaitsev

Subjects
Physics, Solar flare, Space and Planetary Science, Astronomy and Astrophysics, Coronal loop, Astrophysics, Plasma, Low frequency, Capacitance, Microwave, Magnetic field, Electronic circuit
Abstract

Low-frequency (LF) modulations of 37 GHz microwave radiation during solar flares, recorded at the Metsahovi Radio Observatory, are considered. A fast Fourier transformation with a sliding window is used to obtain the dynamic spectra of the LF pulsations. We pay attention to the LF dynamic spectra having a specific multi-track structure, which is supposed to be an indication of a complex multi-loop composition of a flaring region. Application of the equivalent electric circuit models of the loops including the effects of electromagnetic inductive interaction in groups of slowly growing current-carrying magnetic loops allows us to explain and reproduce the main dynamical features of the observed LF modulation dynamic spectra. Each loop is considered as an equivalent electric circuit with variable parameters (resistance, capacitance and inductive coefficients) which depend on shape, scale, position of the loop with respect to other loops, as well as on the plasma parameters and value of the total longitudinal current in the magnetic tube.

Published
2005
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4. 147 GHz VLBI observations: Detection of 3C 273 and 3C 279 on the 3100 km baseline Metsähovi – Pico Veleta

Author

Thomas P. Krichbaum, S. Urpo, S. Navarro, D. A. Graham, P. Könönen, J. A. Zensus, K. Wiik, Albert Greve, J. Peltonen, John Conway, Michael Grewing, P. Sjöman, Roy Booth, Ari Mujunen, Jouko Ritakari, M. Berton, F. Rantakyro, D. John, and E. Oinaskallio

Subjects
Physics, Space and Planetary Science, Baseline (sea), Brightness temperature, Very-long-baseline interferometry, Flux, Astronomy, Astronomy and Astrophysics, Astrophysics, Lower limit
Abstract

We report a successful VLBI observation at 147 GHz (2.1 mm) on the 3 100 km long baseline between the telescopes at Metsahovi (Finland) and Pico Veleta (Spain). The sources 3C 273B and 3C 279 were detected with a SNR of∼10. For these sources we estimate that 25-30% of the total flux is detectable as correlated flux on the 3 100 km baseline, which gives at 147 GHz a lower limit of the brightness temperature of the inner VLBI jet region of ∼1×10 1 0 K.

Published
2002
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5. Search for new flat-spectrum radio sources

Author

S. Wiren, Mauri Valtonen, Harri Teräsranta, and S. Urpo

Subjects
Physics, Radio telescope, X-shaped radio galaxy, Space and Planetary Science, Duty cycle, Extrapolation, Astronomy, Astronomy and Astrophysics, Source counts, Astrophysics, Galactic plane, Declination
Abstract

GHz continuum observations with the Metsahovi Radio telescope are used to identifying new flat spectrum radio sources selected from lower frequency survey data. The sample is complete to sources with a flux higher than 0.5 Jy at 1.4 GHz, 0:5 between 1.4 and 4.85 GHz, declination from 0 to +75 degrees and sources more than 20 from the galactic plane. Additional strong sources from the 5 GHz survey were observed to get the sample as complete as possible down to 1.0 Jy at 22 GHz for extrapolation of source counts to lower flux levels. The new flat spectrum sources will be added to our monitoring sample and their duty cycle will be studied for the coming -ray observatiories AGILE and GLAST.

Published
2001
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6. Millimeter-radio, SOHO/EIT 171 Å features and the polar faculae in the polar zones of the Sun

Author

S. Urpo, V. I. Makarov, Esko Valtaoja, Andrey Tlatov, L. V. Makarova, and A. Riehokainen

Subjects
Physics, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Latitude, Radio telescope, Magnetic loop, Space and Planetary Science, White light, Astrophysics::Solar and Stellar Astrophysics, Polar, Millimeter, Astrophysics::Earth and Planetary Astrophysics
Abstract

In this work we study different manifestations of activity in the polar zones of the Sun in order to gain understanding on the phenomenon of enhanced radio temperature regions (ETR) at high solar latitudes. We have obtained simultaneous radio and optical data during 9 days in 1997. The radio data from the Metsahovi radio telescope, Finland, consisted of 37 GHz and 87 GHz solar maps. White light observations at the Kislovodsk solar mountain station in Russia were used to measure the coordinates of polar faculae groups and diffuse bright structures. We also compared our data with the 171 AEUV SOHO/EIT images for the same time periods. We find the ETRs in general coincide with the relatively dark areas seen in the SOHO/EIT images. Bright structures in the SOHO/EIT maps are, in general, encircled by the polar faculae groups and diffuse bright structures visible in white light. Some of the EUV bright structures appear to be bases of solar plumes. Connections between ETRs and polar faculae are complicated; sometimes polar faculae groups and diffuse bright structures are situated around the ETR maxima or at their borders, sometimes we see the polar faculae groups distributed over the whole ETR area. Some faint ETRs appear to have no associated polar faculae. However, in general there is a correlation between the ETRs, the polar faculae groups, and the bright structures (bases of the plumes and some other features), indicating that they are different manifestations of the same underlying activity. It is possible that magnetic loops in the active areas, traced by the polar faculae, are responsible for the observed radio enhancements.

Published
2001
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7. Microwave tomography of solar magnetic fields

Author

S. Urpo, A. Grebinskij, V. Bogod, K. Shibasaki, G. Gelfreikh, and Silja Pohjolainen

Subjects
Physics, Photosphere, Astrophysics::High Energy Astrophysical Phenomena, General Physics and Astronomy, Astronomy, Astrophysics, Coronal radiative losses, Corona, Magnetic field, Nanoflares, Physics::Space Physics, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, Chromosphere, Microwave
Abstract

We present a new technique for the measure- ment of magnetic elds in the solar chromosphere - corona through observations of its free-free microwave emission in intensity and polarization. We derive the decoupled radi- ation transfer equations for Stoke's parameters of I and V for circular polarized emission in plane-layer inhomo- geneous atmospheres and present a model solutions of in- version problem. We discuss the discrimination between contributions from the corona and the chromosphere to the observed brightness spectra from the quiet Sun and plage regions and propose a practical method of magnetic eld estimates, which was used both with single frequency (the Nobeyama Radioheliograph at 17 GHz) and multi fre- quency (RATAN at 1 16 GHz) observations and discuss the preliminary results. The proposed techniques may be useful as microwave magnetography at the corona base and for checks and improvements in the current problem of extrapolating magnetic elds from photosphere to corona.

Published
2000
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8. [Untitled]

Author

S. Urpo, Hubertus Wöhl, V. Ruždjak, Roman Brajša, Bojan Vršnak, and Silja Pohjolainen

Subjects
Physics, Sunspot, business.industry, media_common.quotation_subject, Astronomy and Astrophysics, Angular velocity, Astrophysics, Statistical weight, Asymmetry, Optics, Space and Planetary Science, Brightness temperature, Differential rotation, Solar rotation, business, Microwave, media_common
Abstract

Daily full-disk solar maps obtained at 37 GHz in the years 1979, 1980, 1981, 1982, 1987, 1988, 1989, 1990, and 1991 are analysed and compared with full-disk solar maps in Hα. A search for a difference in the measured angular rotation velocity for two classes of microwave low-brightness-temperature regions (LTRs), associated and not associated with Hα filaments, is performed. Procedures with and without statistical weights, assigned to angular rotation velocities according to the tracing time, are applied and the statistical significance of the results is discussed. A higher angular rotation velocity is measured for LTRs associated with Hα filaments than for the not-associated ones. This angular velocity difference is interpreted as a consequence of a height difference between these two types of LTR tracers. Changes of the solar differential rotation velocity during the activity cycle measured using LTRs as tracers are explained by the measured cycle-dependence of the association rate between LTRs and Hα filaments. Similarly, the north–south asymmetry in the solar rotation velocity measured tracing LTRs is explained by the measured north–south asymmetry in the association rate between LTRs and Hα filaments. The rotation velocity of LTRs and Hα filaments is on the average more rigid in comparison with sunspots.

Published
1999
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9. Fifteen years monitoring of extragalactic radio sources at 22, 37 and 87 GHz

Author

H. Teräsranta, M. Tornikoski, A. Mujunen, K. Karlamaa, T. Valtonen, N. Henelius, S. Urpo, M. Lainela, T. Pursimo, K. Nilsson, S. Wiren, A. Lähteenmäki, M. Korpi, R. Rekola, P. Heinämäki, M. Hanski, P. Nurmi, K. Kokkonen, P. Keinänen, O. Joutsamo, J. Oksanen, H. Pietil, E. Valtaoja, M. Valtonen, and P. Könönen

Subjects
Physics, Active galactic nucleus, Continuum (measurement), General Physics and Astronomy, Astronomy, Millimeter, Quasar, Astrophysics, Data reduction
Abstract

Over 13600 continuum observations of extragalactic sources are presented. These observations of 157 sources at 22, 37 and 87 GHz more than doubles the millimeter observations of these sources. The data are between 1990.5 and 1995.5, and combined with our earlier published data they form a 15 year database.

Published
1998
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10. Multiresolution analysis of solar mm–wave bursts

Author

A. Krüger, Jürgen Kurths, S. Urpo, Udo Schwarz, and Bernhard Kliem

Subjects
Physics, Spectral index, Fractional Brownian motion, Solar flare, Astrophysics::High Energy Astrophysical Phenomena, Multiresolution analysis, General Physics and Astronomy, Flux, Wavelet transform, Astrophysics, Computational physics, Classical mechanics, Time series, Scaling
Abstract

Two methods of multi-scale time series analysis are applied to solar mm-wavelength flux time profiles in order to assess the diagnostic power of these tools for the exploration of nonlinear energy release processes. Both the multiresolution analysis (MRA), a method based on the wavelet transform, and the structure function analysis (SFA) permit the treatment of non-stationary time series. In addition, the MRA offers a local decomposition of the scaling behavior of the flux variations. Our main emphasis is directed at a decomposition of the contributions of the different time scales to the overall flux profile. The methods yield consistent values of the "spectral index" which describes the scalings contained in the time series. We find that time profiles of bursts are qualitatively analogous to fractional Brownian motion (fBm), possessing long-range temporal correlations. Such correlations are not found in quiet Sun observations. The MRA of six solar mm-wave bursts shows that the radio flux is always composed of contributions from a broad range of time scales. Also during the main phase of bursts, which appears to be structurally analogous to the pre- and post-burst phases at a resolution limit of 1 s, flux fluctuations are enhanced in a broad range of time scales. This suggests that the mm-wave bursts are composed of unresolved elements, just as the pre- and post-burst time profiles. The underlying energy release thus appears to be fragmentary. These results are discussed in terms of the avalanche model and plasma physical models for solar energy release events.

Published
1998
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11. A multifrequency analysis of radio variability of blazars

Author

C. Bongardo, S. Urpo, H. D. Aller, Margo F. Aller, G. de Zotti, Roberto Tagliaferri, Giuseppe Longo, Harri Teräsranta, Angelo Ciaramella, Merja Tornikoski, Anne Lähteenmäki, Leopoldo Milano, A., Ciaramella, C., Bongardo, H. D., Aller, M. F., Aller, G., DE ZOTTI, A., Lahteenmaki, Longo, Giuseppe, Milano, Leopoldo, R., Tagliaferri, H., Terasranta, M., Tornikoski, and AND S., Urpo

Subjects
Radiation mechanisms: non-thermal, FOS: Physical sciences, Flux, Astrophysics, 01 natural sciences, symbols.namesake, Radio continuum: general, Radio observatory, 0103 physical sciences, Planck, signal processing, Blazar, 010303 astronomy & astrophysics, Methods: statistical, Physics, 010308 nuclear & particles physics, Galaxies: BL Lacertae objects: general, Astrophysics (astro-ph), radiation mechanisms, non linear PCA, Astronomy and Astrophysics, Quasar, Galaxies: active, Light curve, CMB cold spot, Intensity (physics), Space and Planetary Science, symbols
Abstract

We have carried out a multifrequency analysis of the radio variability of blazars, exploiting the data obtained during the extensive monitoring programs carried out at the University of Michigan Radio Astronomy Observatory (UMRAO, at 4.8, 8, and 14.5 GHz) and at the Metsahovi Radio Observatory (22 and 37 GHz). Two different techniques detect, in the Metsahovi light curves, evidences of periodicity at both frequencies for 5 sources (0224+671, 0945+408, 1226+023, 2200+420, and 2251+158). For the last three sources consistent periods are found also at the three UMRAO frequencies and the Scargle (1982) method yields an extremely low false-alarm probability. On the other hand, the 22 and 37 GHz periodicities of 0224+671 and 0945+408 (which were less extensively monitored at Metsahovi and for which we get a significant false-alarm probability) are not confirmed by the UMRAO database, where some indications of ill-defined periods about a factor of two longer are retrieved. We have also investigated the variability index, the structure function, and the distribution of intensity variations of the most extensively monitored sources. We find a statistically significant difference in the distribution of the variability index for BL Lac objects compared to flat-spectrum radio quasars (FSRQs), in the sense that the former objects are more variable. For both populations the variability index steadily increases with increasing frequency. The distribution of intensity variations also broadens with increasing frequency, and approaches a log-normal shape at the highest frequencies. We find that variability enhances by 20-30% the high frequency counts of extragalactic radio-sources at bright flux densities, such as those of the WMAP and Planck surveys., Comment: A&A accepted. 12 pages, 16 figures

Published
2004

12. [Untitled]

Author

S. Urpo, E. Valtaoja, Henry Aurass, and Silja Pohjolainen

Subjects
Physics, Astrophysics::High Energy Astrophysical Phenomena, Astronomy and Astrophysics, Observable, Astrophysics::Cosmology and Extragalactic Astrophysics, Electron, Astrophysics, Plasma oscillation, law.invention, Magnetic field, Space and Planetary Science, law, Thermal, Event (particle physics), Microwave, Flare
Abstract

Two small radio flares following the great gamma-ray burst on 11 June 1991 are studied. We analyse the different association of emission features at microwaves, decimeter waves, and soft and hard X-rays for the events. The first flare has well-defined emission features in microwaves and soft and hard X-rays, and a faint decimetric signature well after the hard X-ray burst. It is not certain if the decimetric event is connected to the burst features. The second event is characterized by an almost simultaneous appearance of hard X-ray burst maxima and decimetric narrowband drift bursts, but soft X-ray emission is missing from the event. With the exception of the possibility that the soft X-ray emission is absorbed along the way, the following models can explain the reported differences in the second event: (1) Microwave emission in the second event is produced by ≤150 keV electrons spiraling in the magnetic field relatively low in the corona, while the hard X-ray emission is produced at the beginning of the burst near the loop top as thick-target emission. If the bulk of electrons entered the loop, the low-energy electrons would not be effectively mirrored and would eventually hit the footpoints and cause soft X-ray emission by evaporation, which was not observed. The collisions at the loop top would not produce observable plasma heating. The observed decimetric type III bursts could be created by plasma oscillations caused by electron beams traveling along the magnetic field lines at low coronal heights. (2) Microwave emission is caused by electrons with MeV energies trapped in the large magnetic loops, and the electrons are effectively mirrored from the loop footpoints. The hard X-ray emission can come both from the loop top and the loop footpoints as the accelerated lower energy electrons are not mirrored. The low-energy electrons are not, however, sufficient to create observable soft X-ray emission. The type III emission in this case could be formed either at low coronal heights or in local thick regions in the large loops, high in the corona.

Published
1997
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13. Impulsive acceleration during gradual type solar radio flares

Author

S. Urpo, E. Valtaoja, and Silja Pohjolainen

Subjects
Physics, Atmospheric Science, Astrophysics::High Energy Astrophysical Phenomena, Bremsstrahlung, Aerospace Engineering, Astronomy, Flux, Astronomy and Astrophysics, Astrophysics, Solar radio, Plasma, Acceleration, Wavelength, Geophysics, Space and Planetary Science, Thermal, Extremely high frequency, General Earth and Planetary Sciences
Abstract

Gradual rise and fall type solar radio flares recorded at 37 GHz (8 mm wavelength) are analysed and compared with simultaneous soft and hard X-ray events. Emission measures and plasma temperatures were calculated from the GOES soft X-ray data, and optically thin thermal bremsstrahlung flux at 37 GHz was calculated assuming the same emitting volumes. The main emission mechanism behind the millimeter wave radio flares was determined to be thermal bremsstrahlung although many of the flares showed impulsive, non-thermal features. The radio flares were compared with simultaneous BATSE hard X-ray events, but significant temporal correlation was not found. It is suggested that there might be two different types of gradual radio flares, connected to gradual or more impulsive hard X-ray events. Another explanation for the observed two types would be different viewing angles to the emitting regions.

Published
1997
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14. [Untitled]

Author

Roman Brajša, Bojan Vršnak, A. Schroll, S. Urpo, V. Ruždjak, Hubertus Wöhl, and Silja Pohjolainen

Subjects
Protein filament, Physics, Meteorology, Space and Planetary Science, Brightness temperature, Equator, Differential rotation, Solar rotation, Astronomy and Astrophysics, Astrophysics, Rotation, Maxima, Latitude
Abstract

The solar rotation rate obtained using the microwave Low-brightness-Temperature Regions (LTRs) as tracers in the heliographic range ± 55° from the years 1979–1980, 1981–1982, 1987–1988, and 1989–1991 varied from 3% to 4% in medium latitudes, and below 1% at the equator. Using Hα filaments as tracers at higher latitudes from the years 1979, 1980, 1982, 1984, and 1987, the solar rotation rate variation was between 2% and 8%. This represents an upper limit on the rotation rate variation during the solar activity cycle. Such changes could be caused by short-lived, large-scale velocity patterns on the solar surface. The Sun revealed a higher rotation rate on the average during the maxima of the solar activity cycles 21 and 22, i.e., in the periods 1979–1980 and 1989–1991, respectively, which differs from the rotation rates (lower on the average) in some years, 1981–1982 and 1987–1988, between the activity maximum and minimum (LTR data). Simultaneous comparison of rotation rates from LTRs and Hα filament tracings was possible in very limited time intervals and latitude bands only, and no systematic relationship was found, although the rotation rates determined by LTRs were mostly smaller than the rotation rates determined by Hα filaments. The errors obtained by applying different fitting procedures of the LTR data were analyzed, as well as the influence of the height correction. Finally, the north–south asymmetry in the rotation rate investigated by LTRs indicates that the southern solar hemisphere rotated slower in the periods under consideration, the difference being about 1%. The reliability of all obtained results is discussed and a comparison with other related studies was performed.

Published
1997
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15. A multi-wavelength study of a series of solar flares on June 11, 1991

Author

R Herrmann, S. Urpo, and Silja Pohjolainen

Subjects
Physics, Atmospheric Science, X-ray astronomy, Solar flare, Aerospace Engineering, Astronomy, Astronomy and Astrophysics, Astrophysics, Solar physics, Wavelength, Geophysics, Space and Planetary Science, Temporal resolution, General Earth and Planetary Sciences, H-alpha, Microwave, Radio astronomy
Abstract

On June 11, 1991, at 8:00–9:30 UT, several flares were observed in the active region 6659 (N38W24). We have studied the time development, fine-structures, spectral features, polarization, and correlation between different wavelengths of each of these events. The data used in the analysis are Metsahovi and Bern microwave data, GOES7 soft X-ray data, and other wavelength information from the Solar Geophysical Data.

Published
1996
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16. Helium 10830 Å measurements of the Sun

Author

V. Ruždjak, Bojan Vršnak, T. Sakurai, Roman Brajša, S. Urpo, Hubertus Wöhl, and Silja Pohjolainen

Subjects
Physics, Solar observatory, Astrophysics::Instrumentation and Methods for Astrophysics, Coronal hole, Astronomy, Astronomy and Astrophysics, Astrophysics, Coronal loop, Corona, law.invention, Telescope, Space and Planetary Science, Limb darkening, law, Observatory, Physics::Space Physics, Coronal mass ejection, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

Measurements of the Sun in the near-infrared He i 10830 A absorption line were performed using the echelle spectrograph with a dispersion of 6.71 mA per pixel at the Vacuum Tower Telescope (German Solar Telescopes, Teide Observatory, Izana, Tenerife, Spain) on May 26, 1993. These measurements were compared with full-disc soft X-ray images of the Sun (Japanese solar satellite Yohkoh), full-disc solar images in Hα (Big Bear Solar Observatory), full-disc solar images in the He i 10830 A line (National Solar Observatory, Kitt Peak) and with full-disc microwave solar maps at 37 GHz (Metsahovi Radio Research Station). In the He 10830 A line the Sun displays a limb darkening similar to that in the visible part of the spectrum. Active regions and Hα filaments show a strong absorption in the He 10830 A line, whereas the absorption is weak in coronal holes.

Published
1996
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17. Comparison of mm-wave and X-ray diagnostics of flare plasma

Author

V. V. Zaitsev, A. V. Stepanov, N. M. Bakhareva, and S. Urpo

Subjects
Physics, education.field_of_study, Solar flare, Astrophysics::High Energy Astrophysical Phenomena, Population, Bremsstrahlung, Astronomy and Astrophysics, Astrophysics, Plasma, law.invention, Space and Planetary Science, law, Physics::Space Physics, Plasma diagnostics, Emission spectrum, education, Chromosphere, Flare
Abstract

To compare mm-wave and X-ray diagnostics of solar flare plasma, five flares observed in 1980–1991 in Metsahovi at 22 and 37 GHz and with GOES, SMM, and GRO are studied. The first impulsive peak of the mm-wave bursts under investigation coincides in time with hard X-ray emission. The second gradual component in mm-wave emission coincides with the maximum of the soft X-ray emission measure. The bremsstrahlung mm-wave radiation from hot chromospheric plasma and gyrosynchrotron radiation driven by common population of superthermal electrons are calculated. It is shown that for mm-wave events with the first peak intensity ≤ 100 s.f.u., the thermal bremsstrahlung is more important than the gyrosynchrotron emission. The total energy of fast electrons deduced from the first peak of mm-wave bursts is one to two orders of magnitude less than that determined from the hard X-ray emission in the approximation of a thick-target nonthermal model. That can testify in favour of the hybrid thermal/nonthermal model proposed by Holman and Benka (1992). The emission measure and the energy of evaporated plasma using both mm-wave and soft X-ray data are also determined. For events investigated here the energy of evaporated chromospheric plasma is larger than the total energy of fast electron beams. We have concluded that, for evaporation, additional energy release in the chromosphere is needed. The possibility of such energy release in the framework of an advanced circuit model for solar flares is discussed.

Published
1994
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18. Diagnostics of solar flare and evaporated plasma using mm-wave emission

Author

S. Urpo, A. V. Stepanov, and V. V. Zaitsev

Subjects
Physics, Solar flare, Astrophysics::High Energy Astrophysical Phenomena, Bremsstrahlung, Astronomy and Astrophysics, Plasma, Astrophysics, Plasma oscillation, law.invention, Alfvén wave, Physics::Plasma Physics, Space and Planetary Science, law, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Plasma diagnostics, Atomic physics, Chromosphere, Flare
Abstract

Pulsations of mm-wave emission with a period of about 5 s, which occurred during the impulsive phase of the flare of June 22, 1989, are investigated. It has been shown that these pulsations can be driven by Alfvenic oscillations of a flare loop excited due to upward motion of the chromospheric evaporated plasma. A method is proposed to determine the density and temperature of the evaporated plasma as well as the flare loop magnetic field and loop length in terms of Alfvenic oscillations of the loop and bremsstrahlung mechanism of mm-wave emission. The estimation of evaporated plasma energy has shown that for the flare of June 22, 1989 the energy content in electron beams is insufficient for chromospheric plasma evaporation. It is not excluded that the main energy release process occurs in the chromosphere.

Published
1992
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19. Large-scale patterns on the Sun observed in the millimetric wavelength range

Author

Bojan Vršnak, V. Ruzdjak, H. Teräsranta, S. Jurac, S. Urpo, Silja Pohjolainen, Roman Brajša, and Z. Mouradian

Subjects
Physics, Butterfly diagram, business.industry, Equator, Astronomy and Astrophysics, Astrophysics, Solar physics, Solar prominence, Latitude, Magnetic field, Optics, Space and Planetary Science, Brightness temperature, Astrophysics::Solar and Stellar Astrophysics, H-alpha, Astrophysics::Earth and Planetary Astrophysics, business
Abstract

The nature and behaviour of large-scale patterns on the solar surface, indicated by the areas of brightness-temperature depressions in the millimetric wavelength range, is studied. A large sample of 346 individual, low-temperature regions (LTRs) was employed to provide reliable statistical evidence. An association of 99% was found between the locations of LTRs and the large-scale magnetic field inversion lines, and 60% of the LTRs were associated with the inversion line filaments. A tentative physical association with filaments is reconsidered, and one particularly well-observed case is presented. The heights of the perturbers causing brightness-temperature depressions are discussed. The long-term evolution of the latitudinal distribution of LTRs is presented in a butterfly diagram. Two belts of low-temperature regions outline the active region belts, shifting with them towards the equator during the solar activity cycle. The low-temperature region belts of the forthcoming cycle appear already at the maximum of the actual cycle at latitudes of about 55 °. The superpositions of the temperature minima distributions in the synoptic maps show patterns appearing as ‘giant cells’ and compatible with indications inferred from magnetographic data. The reliability of the inferred cells is considered, and a statistical analysis reveals a negligible probability for an accidental distribution appearing in the form of giant cells.

Published
1992
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20. OJ287 as a binary system

Author

S. Urpo, Gene Byrd, M. Valtonen, L. Valtaoja, E. Valtaoja, Harri Teräsranta, A. Sillanpää, B. Sundelius, and S. Haarala

Subjects
Physics, Black hole, Supermassive black hole, Active galactic nucleus, Gravitational wave, Astrophysics, Binary system, Light curve, Orbital period, Galaxy
Abstract

The historical optical light curve of OJ287 shows repeated outbursts at 11.65 yr intervals. Making use of computer modeling, we interpret this as resulting from a 9 yr orbital period in a binary system. Variability time scales are used to construct a mass model of the binary system, with derived masses of 5.109 M⊙ and 2·107 M⊙, We discuss how binary systems such as in OJ287 may result from mergers of galaxies. We infer that the system must contain also a third supermassive black hole.

Published
2008
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21. On the Rigid Component in the Solar Rotation

Author

S. Pohjolainen, Hubertus Wöhl, B. Vrsnak, R. Brajsa, S. Urpo, V. Ruždjak, Hanslmeier, Arnold, Messerotti, Mauro, and Veronig, Astrid

Subjects
Physics, Component (thermodynamics), Brightness temperature, Rotation velocity, Solar rotation, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Tracing, Microwave
Abstract

A rigid component in the rotation velocity determined by tracing low brightness temperature regions in the microwave regime was found and interpreted in terms of their association rate (39%) with rigidly rotating “pivot-points”.

Published
2001

22. Search for antihelium in cosmic rays

Author

Z.R. Dong, S. Bizzaglia, G. Ambrosi, J. Casaus, M. Pimenta, T. S. Dai, Samuel C.C. Ting, L. Djambazov, B.C. Wang, G. Molinari, A. Klimentov, B. Bertucci, S. X. Wu, R. Pilastrini, G. Lamanna, L.G. Yan, R. Siedling, J. Favier, Philipp Azzarello, J. J. Torsti, Antonino Zichichi, A. Hasan, Mauro Menichelli, L. Ao, Inkyu Park, J.P. Vialle, M. Steuer, P.C. Xia, Peter H. Fisher, Ilya Usoskin, P. G. Rancoita, Jing Wang, F. Palmonari, J. Isbert, M. Ribordy, G. Boella, H. von Gunten, P. Crespo, W. J. Burger, N. Fouque, R. Ionica, Federico Cindolo, J.P. Richeux, R. Cavalletti, D.X. Zhao, U. Roeser, N.A. Chernoplekov, C. G. Yang, Nicolas Produit, M. Buenerd, A. Cotta-Ramusino, R. Flaminio, J. P. Da Cunha, Anselmo Margotti, D. Rapin, V. Plyaskin, W. Kim, Roberto Battiston, G.Y. Zhu, W.Z. Zhu, G. Fluegge, G. Bruni, G. Viertel, P. Levtchenko, E. Fiandrini, G. Laurenti, K. Luebelsmeyer, S. Waldmeier Wicki, S.C. Lee, Yu. Galaktionov, F. Massera, D. Vité, J. Ulbricht, A. Chiarini, Hao Zhang, H. S. Chen, C. Rossin, G. Pancaldi, Felicitas Pauss, S. Recupero, Ciaran Williams, R. Kossakowski, W. Karpinski, J. Alcaraz, F. Barao, P. Yeh, E. Emonet, L.K. Ding, H.T. Liu, E. P. Velikhov, G. Torromeo, M. Basile, G.S. Sun, A. Pevsner, J.L. Yan, X. D. Cai, L. Baldini, F. Mezzanotte, C.L. Liu, L. Bellagamba, S. Blasko, K. Hangarter, J. Berdugo, Adrian Biland, G. Barbier, J. Vandenhirtz, V. Hermel, A. Arefiev, E. Prati, Jose Maria Kenny, R. R. McNeil, T.G. Guzik, B. Meillon, W.K. Gu, G. Kenney, I. D'Antone, J.P. Wefel, Markus Cristinziani, T. Eronen, R. Becker, Y.L. Chuang, P. Bene, B. Alpat, D. Luckey, E. Riihonen, A. Mihul, M. Jongmanns, C.C. Feng, D. Casadei, W. Wallraff, J. Krieger, H.L. Zhuang, G. Castellini, Massimo Gervasi, Zhuoxiang Ren, G. Schwering, W. Hungerford, A. Papi, Timo Laitinen, D. Santos, F. Tenbusch, B. Verlaat, P. Berges, Raffaele Mezzenga, S. Urpo, Ari Mujunen, G. Laborie, V. Shoutko, M. Pauluzzi, Y. S. Lu, G.P. Barreira, Yun Wang, V. Commichau, J. Truemper, A. Pesci, D. Ren, M. Capell, V. Koutsenko, Eino Valtonen, F. Vezzu, P. Cannarsa, C. Camps, T.P. Li, M. Ionica, H. Postema, A. Contin, M. Yang, E. Babucci, U. Becker, A. Lebedev, Dong-Chul Son, P. Giusti, I. Lopes, E. Perrin, F. J. Eppling, D. Alvisi, G. Lu, F. Raupach, C. Maña, P. Extermann, S. M. Ting, H. Hofer, G. Esposito, I. Vetlitsky, G. Sartorelli, M. Lolli, G. Maehlum, E.A. Werner, Fabio Finelli, Z.G. Chen, Werner Lustermann, Giuseppe Levi, X. W. Tang, Tao Song, M. Bourquin, V. Pojidaev, E. Shoumilov, H. Suter, J. D. Burger, Roald Z. Sagdeev, A. Mourao, J. Ritakari, Y. H. Chang, D. Barancourt, N. Dinu, H. Anderhub, Tzihong Chiueh, M. A. Huang, Jorge Dias de Deus, F. Mayet, A. Schultz von Dratzig, Alcaraz, J, Alvisi, D, Alpat, B, Ambrosi, G, Anderhub, H, Ao, L, Arefiev, A, Azzarello, P, Babucci, E, Baldini, L, Basile, M, Barancourt, D, Barao, F, Barbier, G, Barreira, G, Battiston, R, Becker, R, Becker, U, Bellagamba, L, Béné, P, Berdugo, J, Berges, P, Bertucci, B, Biland, A, Bizzaglia, S, Blasko, S, Boella, G, Bourquin, M, Bruni, G, Buenerd, M, Burger, J, Burger, W, Cai, X, Cavalletti, R, Camps, C, Cannarsa, P, Capell, M, Casadei, D, Casaus, J, Castellini, G, Chang, Y, Chen, H, Chen, Z, Chernoplekov, N, Chiarini, A, Chiueh, T, Chuang, Y, Cindolo, F, Commichau, V, Contin, A, Cotta Ramusino, A, Crespo, P, Cristinziani, M, Dacunha, J, Dai, T, Deus, J, Ding, L, Dinu, N, Djambazov, L, D'Antone, I, Dong, Z, Emonet, P, Eppling, F, Eronen, T, Esposito, G, Extermann, P, Favier, J, Feng, C, Fiandrini, E, Finelli, F, Fisher, P, Flaminio, R, Fluegge, G, Fouque, N, Galaktionov, Y, Gervasi, M, Giusti, P, Gu, W, Guzik, T, Hangarter, K, Hasan, A, Hermel, V, Hofer, H, Huang, M, Hungerford, W, Ionica, M, Ionica, R, Isbert, J, Jongmanns, M, Karpinski, W, Kenney, G, Kenny, J, Kim, W, Klimentov, A, Krieger, J, Kossakowski, R, Koutsenko, V, Laborie, G, Laitinen, T, Lamanna, G, Laurenti, G, Lebedev, A, Lee, S, Levi, G, Levtchenko, P, Li, T, Liu, C, Liu, H, Lolli, M, Lopes, I, Lu, G, Lu, Y, Lübelsmeyer, K, Luckey, D, Lustermann, W, Maehlum, G, Maña, C, Margotti, A, Massera, F, Mayet, F, Mcneil, R, Meillon, B, Menichelli, M, Mezzanotte, F, Mezzenga, R, Mihul, A, Molinari, G, Mourao, A, Mujunen, A, Palmonari, F, Pancaldi, G, Papi, A, Park, I, Pauluzzi, M, Pauss, F, Perrin, E, Pesci, A, Pevsner, A, Pilastrini, R, Pimenta, M, Plyaskin, V, Pojidaev, V, Postema, H, Prati, E, Produit, N, Rancoita, P, Rapin, D, Raupach, F, Recupero, S, Ren, D, Ren, Z, Ribordy, M, Richeux, J, Riihonen, E, Ritakari, J, Roeser, U, Roissin, C, Sagdeev, R, Santos, D, Sartorelli, G, Schultzvondratzig, A, Schwering, G, Shoutko, V, Shoumilov, E, Siedling, R, Son, D, Song, T, Steuer, M, Sun, G, Suter, H, Tang, X, Ting, S, Tenbusch, F, Torromeo, G, Torsti, J, Trümper, J, Ulbricht, J, Urpo, S, Usoskin, I, Valtonen, E, Vandenhirtz, J, Velikhov, E, Verlaat, B, Vetlitsky, I, Vezzu, F, Vialle, J, Viertel, G, Vité, D, Vongunten, H, Waldmeierwicki, S, Wallraff, W, Wang, B, Wang, J, Wang, Y, Wefel, J, Werner, E, Williams, C, Wu, S, Xia, P, Yan, J, Yan, L, Yang, C, Yang, M, Yeh, P, Zhang, H, Zhao, D, Zhu, G, Zhu, W, Zhuang, H, Zichichi, A, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), and AMS

Subjects
Astrophysics and Astronomy, Nuclear and High Energy Physics, FOS: Physical sciences, chemistry.chemical_element, Space Shuttle, Cosmic ray, Astrophysics, 7. Clean energy, 01 natural sciences, High Energy Physics - Experiment, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], High Energy Physics - Experiment (hep-ex), FIS/05 - ASTRONOMIA E ASTROFISICA, Rigidity (electromagnetism), 0103 physical sciences, Alpha Magnetic Spectrometer, 010306 general physics, Helium, Physics, 010308 nuclear & particles physics, Astrophysics (astro-ph), Astronomy, Flux ratio, FIS/01 - FISICA SPERIMENTALE, chemistry, Cosmic rays: anti-helium, FIS/04 - FISICA NUCLEARE E SUBNUCLEARE
Abstract

The Alpha Magnetic Spectrometer (AMS) was flown on the space shuttle Discovery during flight STS-91 in a 51.7 degree orbit at altitudes between 320 and 390 km. A total of 2.86 * 10^6 helium nuclei were observed in the rigidity range 1 to 140 GV. No antihelium nuclei were detected at any rigidity. An upper limit on the flux ratio of antihelium to helium of < 1.1 * 10^-6 is obtained., 18 pages, Latex, 9 .eps figures

Published
2000

23. Leptons in near earth orbit

Author

L. Djambazov, P. Giusti, G. Scolieri, I. Lopes, Dawei Zhao, P. G. Rancoita, E. Babucci, U. Becker, F. Vezzu, E. Perrin, F. J. Eppling, G. Barbier, S. M. Ting, S.C. Lee, R. Ionica, F. Palmonari, H. von Gunten, G. Esposito, Z.R. Dong, Federico Cindolo, Changgen Yang, H. T. Liu, Diego Casadei, Yu. Galaktionov, D. Vité, A. Lebedev, U. Roeser, G. Castellini, Dong-Chul Son, Z. L. Ren, J. Alcaraz, Guohuai Zhu, Yun Wang, S. Bizzaglia, A. Arefiev, P. Extermann, H. Hofer, W. Wallraff, Ilya Usoskin, Jing Wang, P. Levtchenko, P. Emonet, T. S. Dai, H. Anderhub, Waclaw Karpinski, E. Fiandrini, R. Becker, P. Cannarsa, R. R. McNeil, D. Rapin, C. Roissin, B.C. Wang, M. Pimenta, E. P. Velikhov, B. Zimmermann, V. Plyaskin, Roald Z. Sagdeev, B. Meillon, H. S. Chen, L. Baldini, J. Casaus, A. Hasan, E. Riihonen, Mauro Menichelli, K. Karlamaa, A. Mihul, Giovanna Bruni, G. Kenney, N. Produit, D. Grandi, M. Ribordy, S. Urpo, W. J. Burger, Merja Tornikoski, Markus Cristinziani, G. Schwering, A. Pesci, I. Vetlitsky, L.G. Yan, I. D'Antone, Y. H. Chang, Tengfei Song, W.Q. Gu, B. Bertucci, D. Barancourt, N. Dinu, V. Commichau, G. Laborie, P. Crespo, Mao-Zhi Yang, J. J. Torsti, M. Jongmanns, Antonino Zichichi, Adrian Biland, V. Postolache, Peter H. Fisher, T. Eronen, C. Camps, J. Berdugo, N. Fouque, J. P. Da Cunha, Massimo Gervasi, J. Vandenhirtz, H. F. Chen, F. Barao, S. Blasko, Zhenyu Zhang, H.L. Zhuang, G. Viertel, E. Shoumilov, Jose Maria Kenny, W. Hungerford, F. Velcea, Y.L. Chuang, O. Grimm, J.L. Yan, K. Wiik, P. Bene, H. Suter, J.P. Richeux, Tzihong Chiueh, V. Hermel, M. Buenerd, Timo Laitinen, M. Capell, A. Papi, Eun-Suk Seo, M. Pauluzzi, R. Siedling, G. Fluegge, W.Z. Zhu, Giovanni Ambrosi, L. Ao, M. Bourquin, D. Ren, G. Lu, C. Maña, V. Koutsenko, Eino Valtonen, Felicitas Pauss, R. Kossakowski, A. Klimentov, G.S. Sun, A. Contin, Samuel C.C. Ting, M. A. Huang, M. J. Boschini, M. Basile, K. Hangarter, Roberto Battiston, A. Pevsner, D. Luckey, F. Mayet, Ciaran Williams, J. Ulbricht, A. Schultz von Dratzig, P. Yeh, G. Laurenti, Claudia Cecchi, S. Waldmeier Wicki, Hao Zhang, Z.G. Chen, S. X. Wu, J. Ritakari, X. D. Cai, J. Trümper, V. Shoutko, Inkyu Park, M. Steuer, P.C. Xia, S.W. Ye, C.L. Liu, L. Bellagamba, G. Lamanna, J. Engelberg, Xiao-Dong Tang, J. P. Vialle, K. Lübelsmeyer, G.P. Barreira, M. Ionica, P. Azzarello, Z. Z. Xu, V. Pojidaev, B. Verlaat, G. Sartorelli, P. Berges, Giuseppe Levi, Lu Yuzhang, Ari Mujunen, Werner Lustermann, Behcet Alpat, J. D. Burger, Frank Raupach, A. Mourao, J.D. Deus, L. Brocco, G. Boella, N.A. Chernoplekov, Anselmo Margotti, W. Kim, M. Kraeber, J. Favier, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), AMS, Alcaraz, J, Alpat, B, Ambrosi, G, Anderhub, H, Ao, L, Arefiev, A, Azzarello, P, Babucci, E, Baldini, L, Basile, M, Barancourt, D, Barao, F, Barbier, G, Barreira, G, Battiston, R, Becker, R, Becker, U, Bellagamba, L, Béné, P, Berdugo, J, Berges, P, Bertucci, B, Biland, A, Bizzaglia, S, Blasko, S, Boella, G, Boschini, M, Bourquin, M, Brocco, L, Bruni, G, Buenerd, M, Burger, J, Burger, W, Cai, X, Camps, C, Cannarsa, P, Capell, M, Casadei, D, Casaus, J, Castellini, G, Cecchi, C, Chang, Y, Chen, H, Chen, Z, Chernoplekov, N, Chiueh, T, Chuang, Y, Cindolo, F, Commichau, V, Contin, A, Crespo, P, Cristinziani, M, Cunha, J, Dai, T, Deus, J, Dinu, N, Djambazov, L, D'Antone, I, Dong, Z, Emonet, P, Engelberg, J, Eppling, F, Eronen, T, Esposito, G, Extermann, P, Favier, J, Fiandrini, E, Fisher, P, Fluegge, G, Fouque, N, Galaktionov, Y, Gervasi, M, Giusti, P, Grandi, D, Grimm, O, Gu, W, Hangarter, K, Hasan, A, Hermel, V, Hofer, H, Huang, M, Hungerford, W, Ionica, M, Ionica, R, Jongmanns, M, Karlamaa, K, Karpinski, W, Kenney, G, Kenny, J, Kim, W, Klimentov, A, Kossakowski, R, Koutsenko, V, Kraeber, M, Laborie, G, Laitinen, T, Lamanna, G, Laurenti, G, Lebedev, A, Lee, S, Levi, G, Levtchenko, P, Liu, C, Liu, H, Lopes, I, Lu, G, Lu, Y, Lübelsmeyer, K, Luckey, D, Lustermann, W, Maña, C, Margotti, A, Mayet, F, Mcneil, R, Meillon, B, Menichelli, M, Mihul, A, Mourao, A, Mujunen, A, Palmonari, F, Papi, A, Park, I, Pauluzzi, M, Pauss, F, Perrin, E, Pesci, A, Pevsner, A, Pimenta, M, Plyaskin, V, Pojidaev, V, Postolache, V, Produit, N, Rancoita, P, Rapin, D, Raupach, F, Ren, D, Ren, Z, Ribordy, M, Richeux, J, Riihonen, E, Ritakari, J, Roeser, U, Roissin, C, Sagdeev, R, Sartorelli, G, Dratzig, A, Schwering, G, Scolieri, G, Seo, E, Shoutko, V, Shoumilov, E, Siedling, R, Son, D, Song, T, Steuer, M, Sun, G, Suter, H, Tang, X, Ting, S, Tornikoski, M, Torsti, J, Trümper, J, Ulbricht, J, Urpo, S, Usoskin, I, Valtonen, E, Vandenhirtz, J, Velcea, F, Velikhov, E, Verlaat, B, Vetlitsky, I, Vezzu, F, Vialle, J, Viertel, G, Vité, D, Gunten, H, Wicki, S, Wallraff, W, Wang, B, Wang, J, Wang, Y, Wiik, K, Williams, C, Wu, S, Xia, P, Yan, J, Yan, L, Yang, C, Yang, M, Ye, S, Yeh, P, Xu, Z, Zhang, H, Zhang, Z, Zhao, D, Zhu, G, Zhu, W, Zhuang, H, Zichichi, A, and Zimmermann, B

Subjects
Nuclear and High Energy Physics, Cosmic Rays, AMS, Cosmic ray, Electron, Astrophysics, Kinetic energy, 01 natural sciences, Spectral line, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Nuclear physics, FIS/05 - ASTRONOMIA E ASTROFISICA, AMS-01, 0103 physical sciences, Alpha Magnetic Spectrometer, AMS, 010306 general physics, 010303 astronomy & astrophysics, Physics, Earth's orbit, Cosmic rays: leptons, Cosmic Rays, cosmic rays, AMS-01, FIS/01 - FISICA SPERIMENTALE, Earth's magnetic field, 13. Climate action, High Energy Physics::Experiment, FIS/04 - FISICA NUCLEARE E SUBNUCLEARE, Lepton
Abstract

The lepton spectra in the kinetic energy ranges 0.2 to 40 GeV for e − and 0.2 to 3 GeV for e + were measured by the Alpha Magnetic Spectrometer (AMS) during space shuttle flight STS–91 at altitudes near 380 km. From the origin of the leptons two distinct spectra were observed: a higher energy spectrum and a substantial second spectrum with positrons much more abundant than electrons. Tracing leptons from the second spectra shows that most of these leptons travel for an extended period of time in the geomagnetic field and that the e + and e − originate from two complementary geographic regions.

Published
2000

24. Protons in near earth orbit

Author

J. Alcaraz, D. Alvisi, B. Alpat, G. Ambrosi, H. Anderhub, L. Ao, A. Arefiev, P. Azzarello, E. Babucci, L. Baldini, M. Basile, D. Barancourt, F. Barao, G. Barbier, G. Barreira, R. Battiston, R. Becker, U. Becker, L. Bellagamba, P. Béné, J. Berdugo, P. Berges, B. Bertucci, A. Biland, S. Bizzaglia, S. Blasko, G. Boella, M. Boschini, M. Bourquin, G. Bruni, M. Buenerd, J.D. Burger, W.J. Burger, X.D. Cai, R. Cavalletti, C. Camps, P. Cannarsa, M. Capell, D. Casadei, J. Casaus, G. Castellini, Y.H. Chang, H.F. Chen, H.S. Chen, Z.G. Chen, N.A. Chernoplekov, A. Chiarini, T.H. Chiueh, Y.L. Chuang, F. Cindolo, V. Commichau, A. Contin, A. Cotta–Ramusino, P. Crespo, M. Cristinziani, J.P. da Cunha, T.S. Dai, J.D. Deus, N. Dinu, L. Djambazov, I. D'Antone, Z.R. Dong, P. Emonet, J. Engelberg, F.J. Eppling, T. Eronen, G. Esposito, P. Extermann, J. Favier, C.C. Feng, E. Fiandrini, F. Finelli, P.H. Fisher, R. Flaminio, G. Fluegge, N. Fouque, Yu. Galaktionov, M. Gervasi, P. Giusti, D. Grandi, W.Q. Gu, K. Hangarter, A. Hasan, V. Hermel, H. Hofer, M.A. Huang, W. Hungerford, M. Ionica, R. Ionica, M. Jongmanns, K. Karlamaa, W. Karpinski, G. Kenney, J. Kenny, W. Kim, A. Klimentov, R. Kossakowski, V. Koutsenko, G. Laborie, T. Laitinen, G. Lamanna, G. Laurenti, A. Lebedev, S.C. Lee, G. Levi, P. Levtchenko, C.L. Liu, H.T. Liu, M. Lolli, I. Lopes, G. Lu, Y.S. Lu, K. Lübelsmeyer, D. Luckey, W. Lustermann, C. Maña, A. Margotti, F. Massera, F. Mayet, R.R. McNeil, B. Meillon, M. Menichelli, F. Mezzanotte, R. Mezzenga, A. Mihul, G. Molinari, A. Mourao, A. Mujunen, F. Palmonari, G. Pancaldi, A. Papi, I.H. Park, M. Pauluzzi, F. Pauss, E. Perrin, A. Pesci, A. Pevsner, R. Pilastrini, M. Pimenta, V. Plyaskin, V. Pojidaev, H. Postema, V. Postolache, E. Prati, N. Produit, P.G. Rancoita, D. Rapin, F. Raupach, S. Recupero, D. Ren, Z. Ren, M. Ribordy, J.P. Richeux, E. Riihonen, J. Ritakari, U. Roeser, C. Roissin, R. Sagdeev, D. Santos, G. Sartorelli, A. Schultz von Dratzig, G. Schwering, E.S. Seo, V. Shoutko, E. Shoumilov, R. Siedling, D. Son, T. Song, M. Steuer, G.S. Sun, H. Suter, X.W. Tang, Samuel C.C. Ting, S.M. Ting, M. Tornikoski, G. Torromeo, J. Torsti, J. Trümper, J. Ulbricht, S. Urpo, I. Usoskin, E. Valtonen, J. Vandenhirtz, F. Velcea, E. Velikhov, B. Verlaat, I. Vetlitsky, F. Vezzu, J.P. Vialle, G. Viertel, D. Vité, H. Von Gunten, S. Waldmeier Wicki, W. Wallraff, B.C. Wang, J.Z. Wang, Y.H. Wang, K. Wiik, C. Williams, S.X. Wu, P.C. Xia, J.L. Yan, L.G. Yan, C.G. Yang, M. Yang, S.W. Ye, P. Yeh, Z.Z. Xu, H.Y. Zhang, Z.P. Zhang, D.X. Zhao, G.Y. Zhu, W.Z. Zhu, H.L. Zhuang, A. Zichichi, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), AMS, Alcaraz, J, Alvisi, D, Alpat, B, Ambrosi, G, Anderhub, H, Ao, L, Arefiev, A, Azzarello, P, Babucci, E, Baldini, L, Basile, M, Barancourt, D, Barao, F, Barbier, G, Barreira, G, Battiston, R, Becker, R, Becker, U, Bellagamba, L, Béné, P, Berdugo, J, Berges, P, Bertucci, B, Biland, A, Bizzaglia, S, Blasko, S, Boella, G, Boschini, M, Bourquin, M, Bruni, G, Buenerd, M, Burger, J, Burger, W, Cai, X, Cavalletti, R, Camps, C, Cannarsa, P, Capell, M, Casadei, D, Casaus, J, Castellini, G, Chang, Y, Chen, H, Chen, Z, Chernoplekov, N, Chiarini, A, Chiueh, T, Chuang, Y, Cindolo, F, Commichau, V, Contin, A, Cotta–ramusino, A, Crespo, P, Cristinziani, M, Cunha, J, Dai, T, Deus, J, Dinu, N, Djambazov, L, D'Antone, I, Dong, Z, Emonet, P, Engelberg, J, Eppling, F, Eronen, T, Esposito, G, Extermann, P, Favier, J, Feng, C, Fiandrini, E, Finelli, F, Fisher, P, Flaminio, R, Fluegge, G, Fouque, N, Galaktionov, Y, Gervasi, M, Giusti, P, Grandi, D, Gu, W, Hangarter, K, Hasan, A, Hermel, V, Hofer, H, Huang, M, Hungerford, W, Ionica, M, Ionica, R, Jongmanns, M, Karlamaa, K, Karpinski, W, Kenney, G, Kenny, J, Kim, W, Klimentov, A, Kossakowski, R, Koutsenko, V, Laborie, G, Laitinen, T, Lamanna, G, Laurenti, G, Lebedev, A, Lee, S, Levi, G, Levtchenko, P, Liu, C, Liu, H, Lolli, M, Lopes, I, Lu, G, Lu, Y, Lübelsmeyer, K, Luckey, D, Lustermann, W, Maña, C, Margotti, A, Massera, F, Mayet, F, Mcneil, R, Meillon, B, Menichelli, M, Mezzanotte, F, Mezzenga, R, Mihul, A, Molinari, G, Mourao, A, Mujunen, A, Palmonari, F, Pancaldi, G, Papi, A, Park, I, Pauluzzi, M, Pauss, F, Perrin, E, Pesci, A, Pevsner, A, Pilastrini, R, Pimenta, M, Plyaskin, V, Pojidaev, V, Postema, H, Postolache, V, Prati, E, Produit, N, Rancoita, P, Rapin, D, Raupach, F, Recupero, S, Ren, D, Ren, Z, Ribordy, M, Richeux, J, Riihonen, E, Ritakari, J, Roeser, U, Roissin, C, Sagdeev, R, Santos, D, Sartorelli, G, Dratzig, A, Schwering, G, Seo, E, Shoutko, V, Shoumilov, E, Siedling, R, Son, D, Song, T, Steuer, M, Sun, G, Suter, H, Tang, X, Ting, S, Tornikoski, M, Torromeo, G, Torsti, J, Trümper, J, Ulbricht, J, Urpo, S, Usoskin, I, Valtonen, E, Vandenhirtz, J, Velcea, F, Velikhov, E, Verlaat, B, Vetlitsky, I, Vezzu, F, Vialle, J, Viertel, G, Vité, D, Gunten, H, Wicki, S, Wallraff, W, Wang, B, Wang, J, Wang, Y, Wiik, K, Williams, C, Wu, S, Xia, P, Yan, J, Yan, L, Yang, C, Yang, M, Ye, S, Yeh, P, Xu, Z, Zhang, H, Zhang, Z, Zhao, D, Zhu, G, Zhu, W, Zhuang, H, and Zichichi, A

Subjects
Nuclear and High Energy Physics, Astrophysics and Astronomy, Proton, FOS: Physical sciences, Flux, Space Shuttle, Astrophysics, Kinetic energy, 7. Clean energy, 01 natural sciences, High Energy Physics - Experiment, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], High Energy Physics - Experiment (hep-ex), FIS/05 - ASTRONOMIA E ASTROFISICA, 0103 physical sciences, Alpha Magnetic Spectrometer, Cosmic rays, AMS, AMS, Nuclear Experiment, 010303 astronomy & astrophysics, Cosmic rays, Physics, Range (particle radiation), Earth's orbit, 010308 nuclear & particles physics, Astrophysics (astro-ph), Earth's magnetic field, FIS/01 - FISICA SPERIMENTALE, 13. Climate action, Physics::Space Physics, cosmic rays: protons, FIS/04 - FISICA NUCLEARE E SUBNUCLEARE, Particle Physics - Experiment
Abstract

The proton spectrum in the kinetic energy range 0.1 to 200 GeV was measured by the Alpha Magnetic Spectrometer (AMS) during space shuttle flight STS-91 at an altitude of 380 km. Above the geomagnetic cutoff the observed spectrum is parameterized by a power law. Below the geomagnetic cutoff a substantial second spectrum was observed concentrated at equatorial latitudes with a flux ~ 70 m^-2 sec^-1 sr^-1. Most of these second spectrum protons follow a complicated trajectory and originate from a restricted geographic region., 19 pages, Latex, 7 .eps figures

Published
2000

25. Millimeter Wave Radiation Sources Visible in Solar Corona

Author

A. Krüger, S. Urpo, and S. Pohjolainen

Subjects
Physics, Electron density, Wavelength, Magnetic loop, Optics, business.industry, Brightness temperature, Extremely high frequency, Coronal mass ejection, Astrophysics, Radio frequency, Radiation, business
Abstract

Coronal millimeter wave sources (CMMS) have been observed at radio frequencies 22-90 GHz (at wavelengths 3-13 mm). The observed CMMS have been classified into three different categories according to their time scale and relation to other wavelength events. The CMMS indicate enhancement of electron density in the corona, as well as magnetic loop structures. The CMMS are evidence of dynamical processes taking place at the lower levels of the corona, propagating into the higher levels.

Published
1994
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26. RELATION BETWEEN CORONAL mm-WAVE SOURCES, NOISE STORMS, AND CMEs

Author

J. Hildebrandt, A. Krüger, S. Urpo, and A. Böhme

Subjects
Physics, Photosphere, Coronal plane, Coronal mass ejection, Coronal cloud, Astronomy, Storm, Astrophysics, Coronal loop, Solar physics, Noise (radio)
Abstract

Coronal millimeter-wave sources (CMMSs) centered at heights in the solar atmosphere of the order of 100000 km above the photospheric level have been observed for more than ten years at the Metsahovi Radio Research Station of the Helsinki University of Technology. The CMMSs appear to form a special class of long-duration post-flare emission although their relationship to single flares is not always clearly established. There is an interesting relation to gradual microwave bursts and noise storms, and also to soft X-ray long-duration events (LDEs) and coronal mass ejections (CMEs). Results of these findings are discussed and consequences for the physical interpretation outlined.

Published
1992
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27. On the association between coronal mm-wave sources, LDE x-ray flares, and coronal mass ejections

Author

J. Hildebrandt, Silja Pohjolainen, S. Urpo, and A. Krüger

Subjects
Physics, Atmospheric Science, Photosphere, Solar flare, Aerospace Engineering, Astronomy, Astronomy and Astrophysics, Coronal loop, Astrophysics, Solar physics, Special class, law.invention, Geophysics, Space and Planetary Science, law, Coronal plane, Coronal mass ejection, General Earth and Planetary Sciences, Flare
Abstract

Coronal millimetre-wave sources (CMMSs) at heights of about 10 5 km above the photosphere and lifetimes of at least several hours are considered to form a special class of post-flare events providing interesting objects for plasma diagnostics. Based on observations for more than six years their relationship to long lasting X-ray emissions (LDEs) and great flare events is examined. Although only a part of CMMSs is found to be associated with LDEs at a time interval

Published
1989
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28. Relationship of solar coronal millimetre wave sources to bursts in the centimetre range

Author

H. Teräsranta, J. Hildebrandt Potsdam, S. Urpo, V. Ruždjak, and A. Krüger

Subjects
Physics, Space and Planetary Science, Astronomy and Astrophysics, Statistical analysis, Astrophysics, Millimetre wave
Abstract

Les relations entre les ondes millimetriques solaires et les sursauts solaires sont analysees. Les ondes millimetriques coronales peuvent etre considerees comme indicateurs de systemes d'arches coronales de grande envergure (∼ 10 5 km) provenant de grandes regions actives solaires

Published
1989
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29. On the correlation of microwave bursts with the Hα flares

Author

H. Teräsranta, S. Urpo, and V. Ruzdjak

Subjects
Physics, Atmospheric Science, Solar flare, Astrophysics::High Energy Astrophysical Phenomena, Aerospace Engineering, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Solar maximum, law.invention, Radio telescope, Solar wind, Geophysics, Space and Planetary Science, law, Observatory, Physics::Space Physics, Coronal mass ejection, Astrophysics::Solar and Stellar Astrophysics, General Earth and Planetary Sciences, Microwave, Flare
Abstract

The results of a direct comparison of solar microwave recordings at the Metsahovi Radio Research station, Finland, and H-alpha flares at the Hvar Observatory, Yugoslavia, during the Solar Maximum Year compaigns of 1979-1981 and 1983 are reported. At the Metsahovi station, a 14-meter radio telescope is used and at the Hvar Observatory a solar double-telescope is used. It is found that the correlation between H-alpha flares and microwave gradual rise and fall events (GRF), with a time scale of tens of minutes, is high. At Metsahovi, 23 GRF events are measured and in 22 cases (96 percent) a simultaneous flare is observed at Hvar. On the other hand, impulsive microwave bursts with a time scale of tens of seconds have low correlation with H-alpha flares. It is shown that the main contribution to the microwave GRF bursts comes from thermal radiation and that the correlation of flares and microwave events is low at long wavelengths and very high at shorter wavelengths. 6 references.

Published
1984
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30. The spectrum of coronal sources at millimetre and centimetre waves

Author

S. Urpo, G. B. Gelfreikh, A. N. Korzhavin, V. M. Bogod, J. Hildebrandt, V. N. Borovik, and A. Krüger

Subjects
Physics, Brightness, Photosphere, business.industry, Bremsstrahlung, Astronomy and Astrophysics, Astrophysics, Polarization (waves), Wavelength, Optics, Space and Planetary Science, Brightness temperature, Degree of polarization, business, Radio wave
Abstract

Recently recognized solar millimetre-wave off-limb sources are interpreted as a special phenomenon of long-duration post- and inter-flare emission at coronal altitudes. We present, for the first time, information about the brightness and polarization spectrum in the centimetre range for one such event of September 22, 1980 by means of RATAN-600 observations. The brightness temperatures observed favour the interpretation of the bulk of the emission by thermal optically thin bremsstrahlung. The degree of polarization measured (p ≈ 0.1–0.2 in the range 7.5–15 GHz) implies quite strong magnetic fields of about ≥300 ± 100 G at a height z > 3 × l04km above the photosphere and indicates a possible contribution of gyromagnetic radiation and/or optically thick bremsstrahlung at longer wavelengths.

Published
1989
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31. A homologous microwave flare on May 29, 1980

Author

S. Urpo

Subjects
Physics, Atmospheric Science, Solar flare, Astrophysics::High Energy Astrophysical Phenomena, Aerospace Engineering, Astronomy, Astronomy and Astrophysics, Astrophysics, Solar physics, Electromagnetic radiation, law.invention, Radio telescope, Wavelength, Geophysics, Space and Planetary Science, law, Rise time, General Earth and Planetary Sciences, Microwave, Flare
Abstract

Two homologous solar bursts were recorded on May 29, 1980 at 1028 UT and at 1147 UT from the Hale region 16864. The measurements were done at 8 mm wavelength at the Metsahovi Radio Research Station using a 14 meter radio telescope. The time series of the bursts were similar even in the small details. The rise time of both bursts was about 10 seconds and the peak flux density was 3.3 sfu at 1028 UT and 1.2 sfu at 1147 UT. Both bursts were composed of several elementary spikes which were typically 3 seconds apart from each other. The maximum of the gyro-synchrotron type spectrum was close to 15 GHz. The time profile of the bursts, elementary spikes and the frequency spectrum indicated that the origin of these homologous microwave bursts was in a magnetic structure with several loops and that the same complex loop structure was producing energy during both bursts.

Published
1982
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32. A 15.7-min periodicity in OJ287

Author

T. Korhonen, Harri Teräsranta, S. Urpo, H. Lehto, Erkki Salonen, Pekka Teerikorpi, William C. Saslaw, Esko Valtaoja, M. Tiuri, Mauri Valtonen, and V. Piirola

Subjects
Physics, Multidisciplinary, 010504 meteorology & atmospheric sciences, business.industry, Astrophysics, Light curve, 01 natural sciences, Redshift, Photometry (optics), Amplitude, Optics, 0103 physical sciences, Orbital motion, Flux quantization, Variable star, business, 010303 astronomy & astrophysics, Optical observation, 0105 earth and related environmental sciences
Abstract

The BL Lac-type object OJ287, with a redshift z = 0.306 and a luminosity exceeding 1047 erg s−1 at maximum light, is among the brightest and most violently variable objects of its class. Rapid variations, with timescales of a few hours or less, have been reported over a wide range of wavelengths1,2 and also in polarization3, imposing strong constraints on the size and dynamics of the source4,5. The detection of periodic variations in OJ287, or in any other compact extragalactic source, would be even more important, as these could be related to rotation or orbital motion in the source. So far the only searches sensitive to periodic variations shorter than 1 h are the photometric observations of Visvanathan and Elliot6, Frohlich et al.7 and Kiplinger8, in which a 40-min period in OJ287 was respectively found, confirmed and not detected. We report here the detection of a 15.7-min periodic flux variation in OJ287 in April 1981 at 37 GHz. The source has been subsequently monitored for 265 h at 22 and 37 GHz, as well as in optical photometry, and the same period has been seen in simultaneous observations. The peak–peak amplitude of the variation is 1–10% of the total intensity. Other periods may also exist.

Published
1985
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33. Cosmic-ray positron fraction measurement from 1 to 30 GeV with AMS-01

Author

Aguilar, M, Alcaraz, J, Allaby, J, Alpat, B, Ambrosi, G, Anderhub, H, L. Ao, A. Arefiev, P. Azzarello, L. Baldini, M. Basile, D. Barancourt, F. Barao, G. Barbier, G. Barreira, R. Battiston, R. Becker, U. Becker, L. Bellagamba, P. Béné, J. Berdugo, P. Berges, B. Bertucci, A. Biland, S. Blasko, Boschini, M, M. Bourquin, L. Brocco, G. Bruni, M. Buénerd, J. D. Burger, W. J. Burger, X. D. Cai, C. Camps, P. Cannarsa, M. Capell, F. Cardano, D. Casadei, J. Casaus, G. Castellini, Y. H. Chang, H. F. Chen, H. S. Chen, Z. G. Chen, N. A. Chernoplekov, T. H. Chiueh, K. Cho, M. J. Choi, Y. Y. Choi, F. Cindolo, V. Commichau, A. Contin, E. Cortina Gil, M. Cristinziani, T. S. Dai, C. Delgado, S. Difalco, L. Djambazov, I. D'Antone, Z. R. Dong, P. Emonet, J. Engelberg, F. J. Eppling, T. Eronen, G. Esposito, P. Extermann, J. Favier, E. Fiandrini, P. H. Fisher, G. Flügge, N. Fouque, Y.u. Galaktionov, H. Gast, P. Giusti, Grandi, D, O. Grimm, W. Q. Gu, K. Hangarter, A. Hasan, V. Hermel, H. Hofer, W. Hungerford, M. Jongmanns, K. Karlamaa, W. Karpinski, G. Kenney, D. H. Kim, G. N. Kim, K. S. Kim, M. Y. Kim, A. Klimentov, R. Kossakowskic, A. Kouninel, V. Koutsenkol, M. Kraeberai, G. Laboriet, T. Laitinenah, G. Lamannaad, 1, E. Lanciottiz, G. Laurentij, A. Lebedevl, C. Lechanoine Lelucs, M. W. Leeo, S. C. Leeag, G. Levij, C. L. Liuy, H. T. Liui, G. Lug, Y. S. Lui, K. Lübelsmeyera, D. Luckeyl, W. Lustermannai, C. Mañaz, A. Margottij, F. Mayett, R. R. McNeild, B. Meillont, M. Menichelliad, A. Mihulk, A. Mujunenv, A. Olivaad, J. Olzema, F. Palmonarij, H. B. Parko, W. H. Parko, M. Pauluzziad, F. Paussai, E. Perrins, A. Pescij, A. Pevsnere, F. Piloae, M. Pimentax, w, V. Plyaskinac, V. Pojidaevac, M. Pohls, N. Produits, Rancoita, PG D. Rapins, F. Raupacha, D. Renai, Z. Renag, M. Ribordys, J. P. Richeuxs, E. Riihonenah, J. Ritakariv, S. Roo, U. Roeserai, C. Rossint, R. Sagdeevn, D. Santost, G. Sartorellij, C. Sbarraj, S. Schaela, A. Schultz von Dratziga, G. Schweringa, E. S. Seon, J. W. Shino, E. Shoumilovac, V. Shoutkol, T. Siedenburgl, R. Siedlinga, D. Sono, T. Songh, F. Spinellaae, M. Steuerl, G. S. Sunh, H. Suterai, X. W. Tangi, Samuel C. C. Tingl, S. M. Tingl, M. Tornikoskiv, J. Torstiah, J. Trümperq, J. Ulbrichtai, S. Urpov, E. Valtonenah, J. Vandenhirtza, E. Velikhovab, B. Verlaatai, 2, I. Vetlitskyac, F. Vezzut, J. P. Viallec, G. Viertelai, D. Vités, H. Von Guntenai, S. Waldmeier Wickiai, W. Wallraffa, B. C. Wangy, J. Z. Wangg, K. Wiikv, C. Williamsj, S. X. Wul, m, P. C. Xiah, S. Xul, J. L. Yang, L. G. Yanh, C. G. Yangi, J. Yangaf, M. Yangi, S. W. Yeu, 3, Z. Z. Xu, H. Y. Zhang, Z. P. Zhang, D. X. Zhao, Y. Zhou, G. Y. Zhu, W. Z. Zhu, H. L. Zhuang, A. Zichichi, B. Zimmermann, P. Zuccon, BOELLA, GIULIANO FILIPPO, GERVASI, MASSIMO, Bene, Pierre, Bourquin, Maurice, Cortina Gil, Eduardo, Cristinziani, Markus, Emonet, Pascal Philippe, Extermann, Pierre, Leluc, Catherine, Perrin, Eric, Pohl, Martin, Produit, Nicolas, Rapin, Divic Jean, Ribordy, Mathieu, Richeux, Jean-Pierre, Vite, Davide, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), AMS, M. AGUILAR, J. ALCARAZ, J. ALLABY, B. ALPAT, G. AMBROSI, H. ANDERHUB, L. AO, A. AREFIEV, P. AZZARELLO, L. BALDINI, M. BASILE, D. BARANCOURT, F. BARAO, G. BARBIER, G. BARREIRA, R. BATTISTON, R. BECKER, U. BECKER, L. BELLAGAMBA, P. BENE, J. BERDUGO, P. BERGES, B. BERTUCCI, A. BILAND, S. BLASKO, G. BOELLA, M. BOSCHINI, M. BOURQUIN, L. BROCCO, G. BRUNI, M. BUENERD, J.D. BURGER, W.J. BURGER, X.D. CAI, C. CAMPS, P. CANNARSA, M. CAPELL, F. CARDANO, D. CASADEI, J. CASAUS, G. CASTELLINI, Y.H. CHANG, H.F. CHEN, H.S. CHEN, Z.G. CHEN, N.A. CHERNOPLEKOV, T.H. CHIUEH, K. CHO, M.J. CHOI, Y.Y. CHOI, F. CINDOLO, V. COMMICHAU, A. CONTIN, E. CORTINA-GIL, M. CRISTINZIANI, T.S. DAI, C. DELGADO, S. DIFALCO, L. DJAMBAZOV, I. D'ANTONE, Z.R. DONG, P. EMONET, J. ENGELBERG, F.J. EPPLING, T. ERONEN, G. ESPOSITO, P. EXTERMANN, J. FAVIER, E. FIANDRINI, P.H. FISHER, G. FLUEGGE, N. FOUQUE, YU. GALAKTIONOV, H. GAST, M. GERVASI, P. GIUSTI, D. GRANDI, O. GRIMM, W.Q. GU, K. HANGARTER, A. HASAN, V. HERMEL, H. HOFER, W. HUNGERFORD, M. JONGMANNS, K. KARLAMAA, W. KARPINSKI, G. KENNEY, D.H. KIM, G.N. KIM, K.S. KIM, M.Y. KIM, A. KLIMENTOV, R. KOSSAKOWSKI, A. KOUNINE, V. KOUTSENKO, M. KRAEBER, G. LABORIE, T. LAITINEN, G. LAMANNA, E. LANCIOTTI, G. LAURENTI, A. LEBEDEV, C. LECHANOINE-LELUC, M.W.LEE, S.C. LEE, G. LEVI, C.L. LIU, H.T. LIU, G. LU, Y.S. LU, K. LUBELSMEYER, D. LUCKEY, W. LUSTERMANN, C. MANA, A. MARGOTTI, F. MAYET, R.R. MCNEIL, B. MEILLON, M. MENICHELLI, A.MIHUL, A. MUJUNEN, A. OLIVA, J. OLZEM, F. PALMONARI, H.B. PARK, W.H. PARK, M. PAULUZZI, F. PAUSS, E. PERRIN, A. PESCI, A. PEVSNER, F. PILO, M. PIMENTA, V. PLYASKIN, V. POJIDAEV, M. POHL, N. PRODUIT, P.G. RANCOITA, D. RAPIN, F. RAUPACH, D. REN, Z. REN, M. RIBORDY, J.P. RICHEAUX, E. RIIHONEN, J. RITAKARI, S. RO, U. ROESER, C. ROSSIN, R. SAGDEEV, D. SANTOS, G. SARTORELLI, C. SBARRA, S. SCHAEL, A. SCHULTZ VON DRATZIG, G. SCHWERING, E.S. SEO, J.W. SHIN, E. SHOUMILOV, V. SHOUTKO, T. SIEDENBURG, R. SIEDLING, D. SON, T. SONG, F. SPINELLA, M. STEUER, G. S. SUN, H. SUTER, X.W. TANG, SAMUEL C.C. TING, S.M. TING, M. TORNIKOSKI, J. TORSTI, J. TRUEMPER, J. ULBRICHT, S. URPO, E. VALTONEN, J. VANDENHIRTZ, E. VELIKHOV, B. VERLAAT, I. VETLITSKI, F. VEZZU, J.P. VIALLE, G. VIERTEL, D. VITE, H. VON GUNTEN, S. WALDMEIER WICKI, W. WALLRAFF, B.C. WANG, J.Z. WANG, K. WIIK, C. WILLIAMS, S.X. WU, P.C. XIA, S. XU, J.L. YAN, L.G. YAN, C.G. YANG, J. YANG, M. YANG, S.W. YE, Z.Z. XU, H.Y. ZHANG, Z.P. ZHANG, D.X. ZHAO, Y. ZHOU, G.Y.ZHU, W.Z. ZHU, H.L. ZHUANG, A. ZICHICHI, B. ZIMMERMANN, P. ZUCCON, Aguilar, M, Alcaraz, J, Allaby, J, Alpat, B, Ambrosi, G, Anderhub, H, L., A, A., A, P., A, L., B, M., B, D., B, F., B, G., B, R., B, U., B, P., B, J., B, B., B, A., B, S., B, Boella, G, Boschini, M, J. D., B, W. J., B, X. D., C, C., C, P., C, M., C, F., C, D., C, J., C, G., C, Y. H., C, H. F., C, H. S., C, Z. G., C, N. A., C, T. H., C, K., C, M. J., C, Y. Y., C, V., C, A., C, E., C, T. S., D, C., D, S., D, L., D, I., D, Z. R., D, P., E, J., E, F. J., E, T., E, G., E, J., F, E., F, P. H., F, G., F, N., F, Galaktionov, Y, H., G, Gervasi, M, P., G, Grandi, D, O., G, W. Q., G, K., H, A., H, V., H, H., H, W., H, M., J, K., K, W., K, G., K, D. H., K, G. N., K, K. S., K, M. Y., K, A., K, R., K, V., K, Ac, M., K, G., L, T., L, E., L, A., L, C., L, M. W., L, S. C., L, C. L., L, H. T., L, Y. S., L, K., L, D., L, W., L, C., M, A., M, F., M, R. R., M, B., M, M., M, A., O, J., O, F., P, H. B., P, W. H., P, M., P, E., P, A., P, W, V., P, N., P, Rancoita, PG D., R, F., R, D., R, Z., R, M., R, J. P., R, E., R, J., R, S., R, U., R, C., R, R., S, D., S, G., S, C., S, S., S, A., S, E. S., S, J. W., S, E., S, V., S, T., S, F., S, M., S, G. S., S, H., S, X. W., T, Samuel C. C., T, S. M., T, M., T, J., T, J., U, S., U, E., V, J., V, B., V, I., V, F., V, J. P., V, G., V, D., V, H., V, S., W, W., W, B. C., W, J. Z., W, K., W, C., W, S. X., W, M, P. C., X, S., X, J. L., Y, L. G., Y, C. G., Y, J., Y, M., Y, S. W., Y, Z. Z., X, H. Y., Z, Z. P., Z, D. X., Z, Y., Z, G. Y., Z, W. Z., Z, H. L., Z, A., Z, B., Z, P., Z, and UCL - SST/IRMP - Institut de recherche en mathématique et physique

Subjects
Raggi cosmici, esperimento AMS, Nuclear and High Energy Physics, Astrophysics and Astronomy, Photon, Proton, Astrophysics::High Energy Astrophysical Phenomena, Cosmic ray, ddc:500.2, Astrophysics, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Nuclear physics, FIS/05 - ASTRONOMIA E ASTROFISICA, Positron, 0103 physical sciences, 010306 general physics, Nuclear Experiment, Physics, Range (particle radiation), 010308 nuclear & particles physics, Bremsstrahlung, Order (ring theory), Cosmic Rays Positrons, AMS experiment, Physics::Accelerator Physics, FIS/04 - FISICA NUCLEARE E SUBNUCLEARE, Energy (signal processing)
Abstract

A measurement of the cosmic ray positron fraction e+ / (e+ + e-) in the energy range of 1-30 GeV is presented. The measurement is based on data taken by the AMS-01 experiment during its 10 day Space Shuttle flight in June 1998. A proton background suppression on the order of 106 is reached by identifying converted bremsstrahlung photons emitted from positrons., Physics Letters B, 646 (4), ISSN:0370-2693, ISSN:0031-9163, ISSN:1873-2445

Published
2007
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34. A STUDY OF COSMIC RAY SECONDARIES INDUCED BY THE MIR SPACE STATION USING AMS-01

Author

Aguilar, M, Alcaraz, J, Allaby, J, Alpat, B, Ambrosi, G, Anderhub, H, L. Aof, A. Arefievg, P. Azzarellod, E. Babuccic, L. Baldinih, i, M. Basileh, D. Barancourtj, F. Baraok, l, G. Barbierj, G. Barreirak, R. Battistonc, R. Beckeri, U. Beckeri, L. Bellagambah, P. Bénéd, J. Berdugoa, P. Bergesi, B. Bertuccic, A. Bilande, S. Bizzagliac, S. Blaskoc, Boschini, M, M. Bourquind, L. Broccoh, G. Brunih, M. Buénerdj, J. D. Burgeri, W. J. Burgerc, X. D. Caii, C. Campsn, P. Cannarsae, M. Capelli, G. Carosii, D. Casadeih, J. Casausa, G. Castellinio, h, C. Cecchic, Y. H. Changp, H. F. Chenq, H. S. Chenr, Z. G. Chenf, N. A. Chernoplekovs, T. H. Chiuehp, K. Chot, M. J. Choiu, Y. Y. Choiu, Y. L. Chuangv, F. Cindoloh, V. Commichaun, A. Continh, E. Cortina Gild, M. Cristinzianid, J. P. da Cunhaw, T. S. Daii, C. Delgadoa, B. Demirközi, J. D. Deusl, N. Dinuc, 1, L. Djambazove, I. D’Antoneh, Z. R. Dongx, P. Emonetd, J. Engelbergy, F. J. Epplingi, T. Eronenz, G. Espositoc, P. Extermannd, J. Favieraa, E. Fiandrinic, P. H. Fisheri, G. Flueggen, N. Fouqueaa, Y.u. Galaktionovg, P. Giustih, Grandi, D, O. Grimme, W. Q. Gux, K. Hangartern, A. Hasane, R. Henning, V. Hermelaa, H. Hofere, M. A. Huangv, W. Hungerforde, M. Ionicac, R. Ionicac, M. Jongmannse, K. Karlamaay, W. Karpinskiab, G. Kenneye, J. Kennyc, D. H. Kimt, G. N. Kimt, K. S. Kimu, M. Y. Kimu, A. Klimentovi, g, R. Kossakowskiaa, V. Koutsenkoi, M. Kraebere, G. Laboriej, T. Laitinenz, G. Lamannac, E. Lanciottia, G. Laurentih, A. Lebedevi, C. Lechanoine Lelucd, M. W. Leet, S. C. Leev, G. Levih, P. Levtchenkoc, 3, C. L. Liuac, H. T. Liur, I. Lopesw, G. Luf, Y. S. Lur, K. Lübelsmeyerab, D. Luckeyi, W. Lustermanne, C. Mañaa, A. Margottih, F. Mayetj, R. R. McNeilad, B. Meillonj, M. Menichellic, A. Mihulae, B. Monreali, A. Mouraol, A. Mujuneny, F. Palmonarih, A. Papic, H. B. Parkt, W. H. Parkt, M. Pauluzzic, F. Pausse, E. Perrind, A. Pescih, A. Pevsneraf, M. Pimentak, V. Plyasking, V. Pojidaevg, M. Pohld, V. Postolachec, N. Produitd, Rancoita, PG, D. Rapind, F. Raupachab, D. Rene, Z. Renv, M. Ribordyd, J. P. Richeuxd, E. Riihonenz, J. Ritakariy, S. Rot, U. Roesere, C. Rossinj, R. Sagdeevag, D. Santosj, G. Sartorellih, C. Sbarrah, S. Schaelab, A. Schultz von Dratzigab, G. Schweringab, G. Scolieric, E. S. Seoag, J. W. Shint, E. Shoumilovg, V. Shoutkoi, R. Siedlingab, D. Sont, T. Songx, M. Steueri, G. S. Sunx, H. Sutere, X. W. Tangr, Samuel C. C. Tingi, S. M. Tingi, M. Tornikoskiy, J. Torstiz, J. Trümperah, J. Ulbrichte, S. Urpoy, E. Valtonenz, J. Vandenhirtzab, F. Velceac, E. Velikhovs, B. Verlaate, 4, I. Vetlitskyg, F. Vezzuj, J. P. Vialleaa, G. Viertele, D. Vitéd, H. Von Guntene, S. Waldmeier Wickie, W. Wallraffab, B. C. Wangac, J. Z. Wangf, Y. H. Wangv, K. Wiiky, C. Williamsh, S. X. Wui, p, P. C. Xiax, J. L. Yanf, L. G. Yanx, C. G. Yangr, J. Yangu, M. Yangr, S. W. Yeq, 5, P. Yehv, Z. Z. Xuq, H. Y. Zhangai, Z. P. Zhangq, D. X. Zhaox, G. Y. Zhur, W. Z. Zhuf, H. L. Zhuangr, A. Zichichih, B. Zimmermann, P. Zuccon, BOELLA, GIULIANO FILIPPO, GERVASI, MASSIMO, M. AGUILAR, J. ALCARAZ, J. ALLABY, B. ALPAT, G. AMBROSI, H. ANDERHUB, L. AO, A. AREFIEV, P. AZZARELLO, E. BABUCCI, L. BALDINI, M. BASILE, D. BARANCOURT, F. BARAO, G. BARBIER, G. BARREIRA, R. BATTISTON, R. BECKER, U. BECKER, L. BELLAGAMBA, P. BENE, J. BERDUGO, P. BERGES, B. BERTUCCI, A. BILAND, S. BIZZAGLIA, S. BLASKO, G. BOELLA, M. BOSCHINI, M. BOURQUIN, L. BROCCO, G. BRUNI, M. BUENERD, J.D. BURGER, W.J. BURGER, X.D. CAI, C. CAMPS, P. CANNARSA, M. CAPELL, G. CAROSI, D. CASADEI, J. CASAUS, G. CASTELLINI, C. CECCHI, Y.H. CHANG, H.F. CHEN, H.S. CHEN, Z.G. CHEN, N.A. CHERNOPLEKOV, T.H. CHIUEH, K. CHO, M.J. CHOI, Y.Y. CHOI, Y.L. CHUANG, F. CINDOLO, V. COMMICHAU, A. CONTIN, E. CORTINA-GIL, M. CRISTINZIANI, J.P. DA CUNHA, T.S. DAI, C. DELGADO, B. DEMIRKOEZ, J.D. DEUS, N. DINU, L. DJAMBAZOV, I. D'ANTONE, Z.R. DONG, P. EMONET, J. ENGELBERG, F.J. EPPLING, T. ERONEN, G. ESPOSITO, P. EXTERMANN, J. FAVIER, E. FIANDRINI, P.H. FISHER, G. FLUEGGE, N. FOUQUE, YU. GALAKTIONOV, M. GERVASI, P. GIUSTI, D. GRANDI, O. GRIMM, W.Q. GU, K. HANGARTER, H. HASAN, R. HENNING, V. HERMEL, H. HOFER, M.A. HUANG, W. HUNGERFORD, M. IONICA, R. IONICA, M. JONGMANNS, K. KARLAMAA, W. KARPINSKI, G. KENNEY, J. KENNY, D.H. KIM, G.N. KIM, K.S. KIM, M.Y. KIM, A. KLIMENTOV, R. KOSSAKOWSKI, V. KOUTSENKO, M. KRAEBER, G. LABORIE, T. LAITINEN, G. LAMANNA, E. LANCIOTTI, G. LAURENTI, A. LEBEDEV, C. LECHANOINE-LELUC, M.W.LEE, S.C. LEE, G. LEVI, P. LEVTCHENKO, C.L. LIU, H.T. LIU, I. LOPES, G. LU, Y.S. LU, K. LUBELSMEYER, D. LUCKEY, W. LUSTERMANN, C. MANA, A. MARGOTTI, F. MAYET, R.R. MCNEIL, B. MEILLON, M. MENICHELLI, A. MIHUL, B. MONREAL, A. MOURAO, A. MUJUNEN, F. PALMONARI, A. PAPI, H.B. PARK, W.H. PARK, M. PAULUZZI, F. PAUSS, E. PERRIN, A. PESCI, A. PEVSNER, M. PIMENTA, V. PLYASKIN, V. POJIDAEV, M. POHL, V. POSTOLACHE, N. PRODUIT, P.G. RANCOITA, D. RAPIN, F. RAUPACH, D. REN, Z. REN, M. RIBORDY, J.P. RICHEAUX, E. RIIHONEN, J. RITAKARI, S. RO, U. ROESER, C. ROSSIN, R. SAGDEEV, D. SANTOS, G. SARTORELLI, C. SBARRA, S. SCHAEL, A. SCHULTZ VON DRATZIG, G. SCHWERING, G. SCOLIERI, E.S. SEO, J.W. SHIN, E. SHOUMILOV, V. SHOUTKO, R. SIEDLING, D. SON, T. SONG, M. STEUER, G. S. SUN, H. SUTER, X.W. TANG, SAMUEL C.C. TING, S.M. TING, M. TORNIKOSKI, J. TORSTI, J. TRUEMPER, J. ULBRICHT, S. URPO, E. VALTONEN, J. VANDENHIRTZ, F. VELCEA, E. VELIKHOV, B. VERLAAT, I. VETLITSKI, F. VEZZU, J.P. VIALLE, G. VIERTEL, D. VITE, H. VON GUNTEN, S. WALDMEIER WICKI, W. WALLRAFF, B.C. WANG, J.Z. WANG, Y.H. WANG, K. WIIK, C. WILLIAMS, S.X. WU, P.C. XIA, J.L. YAN, L.G. YAN, C.G. YANG, J. YANG, M. YANG, S.W. YE, P. YEH, Z.Z. XU, H.Y. ZHANG, Z.P. ZHANG, D.X. ZHAO, G.Y. ZHU, W.Z. ZHU, H.L. ZHUANG, A. ZICHICHI, B. ZIMMERMANN, P. ZUCCON, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), AMS, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, CIEMAT, E-28040 Madrid, Spain6, UCL - SST/IRMP - Institut de recherche en mathématique et physique, Ambrosi, Giovanni, Azzarello, Philipp, Bene, Pierre, Bourquin, Maurice, Cortina Gil, Eduardo, Cristinziani, Markus, Emonet, Pascal Philippe, Leluc, Catherine, Perrin, Eric, Pohl, Martin, Produit, Nicolas, Rapin, Divic Jean, Ribordy, Mathieu, Richeux, Jean-Pierre, Vite, Davide, Aguilar, M, Alcaraz, J, Allaby, J, Alpat, B, Ambrosi, G, Anderhub, H, L., A, A., A, P., A, E., B, L., B, I, M., B, D., B, F., B, L, G., B, R., B, U., B, P., B, J., B, B., B, A., B, S., B, Boella, G, Boschini, M, J. D., B, W. J., B, X. D., C, C., C, P., C, M., C, G., C, D., C, J., C, H, Y. H., C, H. F., C, H. S., C, Z. G., C, N. A., C, T. H., C, K., C, M. J., C, Y. Y., C, Y. L., C, F., C, V., C, A., C, E., C, J. P., D, T. S., D, C., D, B., D, J. D., D, N., D, L., D, I., D, Z. R., D, P., E, J., E, F. J., E, T., E, G., E, J., F, E., F, P. H., F, G., F, N., F, Galaktionovg, Y, Gervasi, M, P., G, Grandi, D, O., G, W. Q., G, K., H, A., H, R., H, V., H, H., H, M. A., H, W., H, M., I, R., I, M., J, K., K, W., K, G., K, J., K, D. H., K, G. N., K, K. S., K, M. Y., K, A., K, G, R., K, V., K, M., K, G., L, T., L, E., L, A., L, C., L, M. W., L, S. C., L, P., L, C. L., L, H. T., L, I., L, Y. S., L, K., L, D., L, W., L, C., M, A., M, F., M, R. R., M, B., M, M., M, F., P, A., P, H. B., P, W. H., P, M., P, E., P, V., P, N., P, Rancoita, P, D., R, F., R, Z., R, M., R, J. P., R, E., R, J., R, S., R, U., R, C., R, R., S, D., S, G., S, C., S, S., S, A., S, E. S., S, J. W., S, E., S, V., S, T., S, M., S, G. S., S, H., S, X. W., T, Samuel C. C., T, S. M., T, M., T, J., T, J., U, S., U, E., V, J., V, F., V, B., V, I., V, J. P., V, G., V, D., V, H., V, S., W, W., W, B. C., W, J. Z., W, Y. H., W, K., W, C., W, S. X., W, P, P. C., X, J. L., Y, L. G., Y, C. G., Y, J., Y, M., Y, S. W., Y, P., Y, Z. Z., X, H. Y., Z, Z. P., Z, D. X., Z, G. Y., Z, W. Z., Z, H. L., Z, A., Z, B., Z, and P., Z

Subjects
Nuclear and High Energy Physics, FIS/06 - FISICA PER IL SISTEMA TERRA E PER IL MEZZO CIRCUMTERRESTRE, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, satellite, interaction, Space Shuttle, Cosmic ray, Field of view, Astrophysics, ddc:500.2, 01 natural sciences, pi, High Energy Physics - Experiment, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], FIS/05 - ASTRONOMIA E ASTROFISICA, cosmic rays, primary, 0103 physical sciences, International Space Station, Alpha Magnetic Spectrometer, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], AMS, 010303 astronomy & astrophysics, Instrumentation, Cosmic rays, Physics, 010308 nuclear & particles physics, space shuttle, Space shuttle, Astronomy, Mir, magnetic spectrometer, Cosmic rays, Spallation, AMS, Mir, Space shuttle, spallation, flux, Energy particle, 13.85.Tp, 25.40.Sc, 29.30.Aj, 95.55.Vj, 95.85.Ry, cosmic radiation, muon, ams, 13. Climate action, Muon flux, Spallation, FIS/04 - FISICA NUCLEARE E SUBNUCLEARE, Particle Physics - Experiment
Abstract

The Alpha Magnetic Spectrometer (AMS-02) is a high energy particle physics experiment that will study cosmic rays in the $\sim 100 \mathrm{MeV}$ to $1 \mathrm{TeV}$ range and will be installed on the International Space Station (ISS) for at least 3 years. A first version of AMS-02, AMS-01, flew aboard the space shuttle \emph{Discovery} from June 2 to June 12, 1998, and collected $10^8$ cosmic ray triggers. Part of the \emph{Mir} space station was within the AMS-01 field of view during the four day \emph{Mir} docking phase of this flight. We have reconstructed an image of this part of the \emph{Mir} space station using secondary $\pi^-$ and $\mu^-$ emissions from primary cosmic rays interacting with \emph{Mir}. This is the first time this reconstruction was performed in AMS-01, and it is important for understanding potential backgrounds during the 3 year AMS-02 mission., Comment: To be submitted to NIM B Added material requested by referee. Minor stylistic and grammer changes

Published
2004
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