10 results on '"Taro Sakao"'
Search Results
2. The Hinode (Solar-B) Mission: An Overview
- Author
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Masumi Shimojo, George A. Doschek, Takashi Watanabe, Sumitaka Tachikawa, Kiyoshi Ichimoto, L. D. Hill, Taro Sakao, Kenji Minesugi, Leon Golub, Shigenobu Shimada, Louise K. Harra, Yoshinori Suematsu, Akira Ohnishi, Tatsuaki Hashimoto, Y. Sone, Hirohisa Hara, T. Yamada, Saku Tsuneta, Toshifumi Shimizu, A. M. Title, J. L. Culhane, Takeo Kosugi, John M. Davis, K. Matsuzaki, and J. K. Owens
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Physics ,Astronautics ,business.industry ,Payload ,Astronomy and Astrophysics ,X-ray telescope ,Space exploration ,law.invention ,Telescope ,Space and Planetary Science ,Observatory ,law ,Satellite ,Aerospace engineering ,business ,Aerospace ,Remote sensing - Abstract
著者人数:25名, Accepted: 2007-07-30, 資料番号: SA1000203000
- Published
- 2007
3. Energetics and Dynamics of an Impulsive Flare on March 10, 2001
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Keiji Yoshimura, Anita Joshi, Rajmal Jain, Takeo Kosugi, Wahab Uddin, M. R. Deshpande, Taro Sakao, and Ramesh Chandra
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Physics ,Spatial correlation ,Solar flare ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Astronomy ,Astronomy and Astrophysics ,Magnetic reconnection ,Electron ,Astrophysics ,Rotation ,law.invention ,Magnetogram ,Space and Planetary Science ,law ,Electric field ,Flare - Abstract
We present the H$\alpha$ observations from ARIES, Nainital of a compact and impulsive solar flare occurred on March 10, 2001 and associated with a CME. We have also analysed HXT, SXT/Yohkoh observations as well as radio observations from Nobeyama Radio Observatory to derive the energetics and dynamics of this impulsive flare. We co-align the H$\alpha$, SXR, HXR, MW and magnetogram images within the instrumental spatial resolution limit. We detect a single HXR source in this flare, which is found spatially associated with one of the H$\alpha$ bright kernel. The unusual feature of HXR and H$\alpha$ sources, observed for the first time, is the rotation during the impulsive phase in clockwise direction. We propose that the rotation may be due to asymmetric progress of the magnetic reconnection site or may be due to the change of peak point of the electric field. In MW emission we found two sources, one is main source which is at the main flare site and another is remote source located in South-West direction. It appears that the remote source is formed by the impact of accelerated energetic electrons from the main flare site. From the spatial co-relation of multi-wavelength images of th, Comment: Accepted in Solar Physics, 20 pages, 12 Figures
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- 2006
4. Multi-Wavelength Observations of an Unusual Impulsive Flare Associated with Cme
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Taro Sakao, Ramesh Chandra, Rajmal Jain, Wahab Uddin, Keiji Yoshimura, Anita Joshi, Takeo Kosugi, and M. R. Despande
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Physics ,Solar flare ,Polarity (physics) ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Flux ,Astronomy and Astrophysics ,Multi wavelength ,Astrophysics ,Magnetic flux ,law.invention ,Space and Planetary Science ,law ,Physics::Space Physics ,Coronal mass ejection ,Astrophysics::Solar and Stellar Astrophysics ,Ejecta ,Flare - Abstract
We present the results of a detailed analysis of multi-wavelength observations of a very impulsive solar flare 1B/M6.7, which occurred on 10 March, 2001 in NOAA AR 9368 (N27 W42). The observations show that the flare is very impulsive with very hard spectrum in HXR that reveal non-thermal emission was most dominant. On the other hand this flare also produced type II radio burst and coronal mass ejections (CME), which are not general characteristics for impulsive flares. In H$\alpha$ we observed the bright mass ejecta (BME) followed by drak mass ejecta (DME). Based on the consistence of the onset times and direction of BME and CME, we conclude that these two phenomena are closely associated. It is inferred that the energy build-up took place due to photospheric reconnection between emerging positive parasitic polarity and predominant negative polarity, which resulted as a consequence of flux cancellation. The shear increased to $>80^o$ due to further emergence of positive parasitic polarity causing strongly enhanced cancellation of flux. It appears that such enhanced magnetic flux cancellation in a strongly sheared region triggered the impulsive flare., Comment: 14 pages, 8 Figures, Accepted for the publication in Solar Physics
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- 2004
5. [Untitled]
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Taro Sakao, Hirohisa Hara, Ken Kobayashi, Shin Nagata, Kazuyoshi Kumagai, Saku Tsuneta, Ryohei Kano, Toshifumi Shimizu, and Tsuyoshi Yoshida
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Physics ,Sounding rocket ,business.industry ,Astronomy ,Astronomy and Astrophysics ,Field of view ,law.invention ,Telescope ,symbols.namesake ,Wavelength ,Optics ,Space and Planetary Science ,law ,Extreme ultraviolet ,symbols ,Angular resolution ,Emission spectrum ,business ,Doppler effect - Abstract
We present an overview and instrumental details of the solar XUV Doppler Telescope (XDT) launched in January 1998 with the S520CN-22 sounding rocket of the Institute of Space and Astronautical Science. The XDT observes nearly single-temperature solar corona at 1.8 MK with angular resolution of ≈ 5′′ pixel size, together with the ability to detect the coronal velocity field with a full-Sun field of view. By use of normal incidence optics whose primary and secondary mirrors are coated with multilayer materials in two sectors, the XDT takes images of the Sun in a set of shorter and longer wavelength bands around the Fe xiv 211.3 A emission line. Summation of a pair of images in the two bands provides an image of the 1.8 MK-corona while the difference between the two provides velocity images of the Fe xiv-emitting plasma. A brief description on the observation sequence together with the flight result is also given.
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- 1999
6. Particle acceleration in flares
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Taro Sakao, Markus J. Aschwanden, Shinzo Enome, Gordon D. Holman, Martin Volwerk, Howard A. Garcia, A. V. Stepanov, V. G. Kurt, Takeo Kosugi, Edward L. Chupp, Arnold O. Benz, and S. G. Benka
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Physics ,X-ray astronomy ,Solar flare ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy and Astrophysics ,Astrophysics ,Gamma-ray astronomy ,Solar physics ,law.invention ,Particle acceleration ,Space and Planetary Science ,law ,Electric field ,Astrophysics::Solar and Stellar Astrophysics ,Radio astronomy ,Flare - Abstract
Particle acceleration is intrinsic to the primary energy release in the impulsive phase of solar flares, and we cannot understand flares without understanding acceleration. New observations in soft and hard X-rays, γ-rays and coherent radio emissions are presented, suggesting flare fragmentation in time and space. X-ray and radio measurements exhibit at least five different time scales in flares. In addition, some new observations of delayed acceleration signatures are also presented. The theory of acceleration by parallel electric fields is used to model the spectral shape and evolution of hard X-rays. The possibility of the appearance of double layers is further investigated.
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- 1994
7. Yohkoh observations of the creation of high-temperature plasma in the flare of 16 December 1991
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Takeo Kosugi, A. T. Phillips, Takashi Sakurai, A. Fludra, J. L. Culhane, Taro Sakao, Kazuo Makishima, C. D. Pike, M. Inda-Koide, George A. Doschek, H. Kurokawa, and R. D. Bentley
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Physics ,X-ray astronomy ,Spectrometer ,Solar flare ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy ,Astronomy and Astrophysics ,X-ray telescope ,Astrophysics ,Plasma ,Solar physics ,law.invention ,Space and Planetary Science ,law ,Physics::Space Physics ,Astrophysics::Solar and Stellar Astrophysics ,Chromosphere ,Flare - Abstract
Yohkoh observations of an impulsive solar flare which occurred on 16 December, 1991 are presented. This flare was a GOES M2.7 class event with a simple morphology indicative of a single flaring loop. X-ray images were taken with the Hard X-ray Telescope (HXT) and soft X-ray spectra were obtained with the Bragg Crystal Spectrometer (BCS) on board the satellite. The spectrometer observations were made at high sensivity from the earliest stages of the flare, are continued throughout the rise and decay phases, and indicate extremely strong blueshifts, which account for the majority of emission in Caxix during the initial phase of the flare. The data are compared with observations from other space and ground-based instruments. A balance calculation is performed which indicates that the energy contained in non-thermal electrons is sufficient to explain the high temperature plasma which fills the loop. The cooling of this plasma by thermal conduction is independently verified in a manner which indicates that the loop filling factor is close to 100%. The production of ‘superhot’ plasma in impulsive events is shown to differ in detail from the morphology and mechanisms appropriate for more gradual events.
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- 1994
8. The Hard X-ray Telescope (HXT) for the SOLAR-A mission
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Takeo Kosugi, Taro Sakao, Keizo Kai, Kazuo Makishima, M. Sawa, Satoshi Masuda, Tadayasu Dotani, Kiyoto Shibasaki, Y. Ogawara, M. Inda, Hiroshi Nakajima, and T. Murakami
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Physics ,Photon ,Solar flare ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy ,Astronomy and Astrophysics ,Field of view ,Collimator ,X-ray telescope ,Astrophysics ,law.invention ,Telescope ,Acceleration ,Space and Planetary Science ,law ,Angular resolution - Abstract
著者人数:12名, 資料番号: SA1001982000
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- 1991
9. New observations of the cyclotron absorption feature in Hercules X–1
- Author
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Sigenori Miyamoto, Takaya Ohashi, P. E. Boynton, Shunji Kitamoto, Kazuo Makishima, T. Mihara, Fumiaki Nagase, Yoshiaki Tanaka, Makoto Tashiro, J. E. Deeter, and Taro Sakao
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Physics ,Multidisciplinary ,Astrophysics::High Energy Astrophysical Phenomena ,Cyclotron ,X-ray binary ,Astrophysics ,Spectral line ,Binary pulsar ,Electron cyclotron resonance ,law.invention ,Neutron star ,Pulsar ,law ,Observatory - Abstract
The Ginga satellite observatory has been used to measure a cyclotron feature in the hard X-ray spectrum of the 1.24-s binary pulsar Hercules X-1 with a much greater energy resolution than in previous observations. The spectrum from 10-60 keV can be described with a simple analytical formula which indicates an absorption feature at about 34 keV rather than an emission feature at about 50 keV. From this, the surface magnetic field strength of Her X-1 is estimated to be (2.9 + or - 0.3) x 10 to the 12th G.
- Published
- 1990
10. Spin-down of the X-ray pulsar GX1 +4 during an extended low state
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Yuzuru Tawara, Fumiaki Nagase, Takaya Ohashi, Kazuhisa Mitsuda, H. Inoue, Taro Sakao, H. D. Thomas, Katsuji Koyama, F. Makino, Kazuo Makishima, Tadayasu Dotani, T. Kii, and Martin J. L. Turner
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Physics ,Orders of magnitude (bit rate) ,Neutron star ,Multidisciplinary ,Pulsar ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy ,Binary number ,Astrophysics ,Spinning ,Spin-½ ,Pulse (physics) ,X-ray pulsar - Abstract
著者人数:13名, Accepted: 1988-05-02, 資料番号: SA1001350000
- Published
- 1988
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