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54 results on '"Reale F"'

3. First light observations of the solar wind in the outer corona with the Metis coronagraph

Author

Romoli, M., primary, Antonucci, E., additional, Andretta, V., additional, Capuano, G. E., additional, Da Deppo, V., additional, De Leo, Y., additional, Downs, C., additional, Fineschi, S., additional, Heinzel, P., additional, Landini, F., additional, Liberatore, A., additional, Naletto, G., additional, Nicolini, G., additional, Pancrazzi, M., additional, Sasso, C., additional, Spadaro, D., additional, Susino, R., additional, Telloni, D., additional, Teriaca, L., additional, Uslenghi, M., additional, Wang, Y.-M., additional, Bemporad, A., additional, Capobianco, G., additional, Casti, M., additional, Fabi, M., additional, Frassati, F., additional, Frassetto, F., additional, Giordano, S., additional, Grimani, C., additional, Jerse, G., additional, Magli, E., additional, Massone, G., additional, Messerotti, M., additional, Moses, D., additional, Pelizzo, M.-G., additional, Romano, P., additional, Schühle, U., additional, Slemer, A., additional, Stangalini, M., additional, Straus, T., additional, Volpicelli, C. A., additional, Zangrilli, L., additional, Zuppella, P., additional, Abbo, L., additional, Auchère, F., additional, Aznar Cuadrado, R., additional, Berlicki, A., additional, Bruno, R., additional, Ciaravella, A., additional, D’Amicis, R., additional, Lamy, P., additional, Lanzafame, A., additional, Malvezzi, A. M., additional, Nicolosi, P., additional, Nisticò, G., additional, Peter, H., additional, Plainaki, C., additional, Poletto, L., additional, Reale, F., additional, Solanki, S. K., additional, Strachan, L., additional, Tondello, G., additional, Tsinganos, K., additional, Velli, M., additional, Ventura, R., additional, Vial, J.-C., additional, Woch, J., additional, and Zimbardo, G., additional

Published
2021
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4. The first coronal mass ejection observed in both visible-light and UV H I Ly-αchannels of the Metis coronagraph on board Solar Orbiter

Author

Andretta, V., primary, Bemporad, A., additional, De Leo, Y., additional, Jerse, G., additional, Landini, F., additional, Mierla, M., additional, Naletto, G., additional, Romoli, M., additional, Sasso, C., additional, Slemer, A., additional, Spadaro, D., additional, Susino, R., additional, Talpeanu, D.-C., additional, Telloni, D., additional, Teriaca, L., additional, Uslenghi, M., additional, Antonucci, E., additional, Auchère, F., additional, Berghmans, D., additional, Berlicki, A., additional, Capobianco, G., additional, Capuano, G. E., additional, Casini, C., additional, Casti, M., additional, Chioetto, P., additional, Da Deppo, V., additional, Fabi, M., additional, Fineschi, S., additional, Frassati, F., additional, Frassetto, F., additional, Giordano, S., additional, Grimani, C., additional, Heinzel, P., additional, Liberatore, A., additional, Magli, E., additional, Massone, G., additional, Messerotti, M., additional, Moses, D., additional, Nicolini, G., additional, Pancrazzi, M., additional, Pelizzo, M.-G., additional, Romano, P., additional, Schühle, U., additional, Stangalini, M., additional, Straus, Th., additional, Volpicelli, C. A., additional, Zangrilli, L., additional, Zuppella, P., additional, Abbo, L., additional, Aznar Cuadrado, R., additional, Bruno, R., additional, Ciaravella, A., additional, D’Amicis, R., additional, Lamy, P., additional, Lanzafame, A., additional, Malvezzi, A. M., additional, Nicolosi, P., additional, Nisticò, G., additional, Peter, H., additional, Plainaki, C., additional, Poletto, L., additional, Reale, F., additional, Solanki, S. K., additional, Strachan, L., additional, Tondello, G., additional, Tsinganos, K., additional, Velli, M., additional, Ventura, R., additional, Vial, J.-C., additional, Woch, J., additional, and Zimbardo, G., additional

Published
2021
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5. MHD Modelling of Coronal Loops: Injection of High-Speed Chromospheric Flows

Author

Petralia, A, Reale, F, Orlando, S, and Klimchuk, J. A

Subjects
Numerical Analysis, Plasma Physics, Solar Physics
Abstract

Context. Observations reveal a correspondence between chromospheric type II spicules and bright upward-moving fronts in the corona observed in the extreme-ultraviolet (EUV) band. However, theoretical considerations suggest that these flows are probably not the main source of heating in coronal magnetic loops. Aims. We investigate the propagation of high-speed chromospheric flows into coronal magnetic flux tubes and the possible production of emission in the EUV band. Methods. We simulated the propagation of a dense 104 K chromospheric jet upward along a coronal loop by means of a 2D cylindrical MHD model that includes gravity, radiative losses, thermal conduction, and magnetic induction. The jet propagates in a complete atmosphere including the chromosphere and a tenuous cool (approximately 0.8 MK) corona, linked through a steep transition region. In our reference model, the jet initial speed is 70 km per second, its initial density is 10(exp 11) per cubic centimeter, and the ambient uniform magnetic field is 10 G. We also explored other values of jet speed and density in 1D and different magnetic field values in 2D, as well as the jet propagation in a hotter (approximately 1.5 MK) background loop. Results. While the initial speed of the jet does not allow it to reach the loop apex, a hot shock-front develops ahead of it and travels to the other extreme of the loop. The shock front compresses the coronal plasma and heats it to about 10(exp 6) K. As a result, a bright moving front becomes visible in the 171 Angstrom channel of the SDO/AIA mission. This result generally applies to all the other explored cases, except for the propagation in the hotter loop. Conclusions. For a cool, low-density initial coronal loop, the post-shock plasma ahead of upward chromospheric flows might explain at least part of the observed correspondence between type II spicules and EUV emission excess.

Published
2014
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6. MHD Modeling of Coronal Loops: the Transition Region Throat

Author

Guarrasi, M, Reale, F, Orlando, S, Mignone, A, and Klimchuk, J. A

Subjects
Plasma Physics
Abstract

Context. The expansion of coronal loops in the transition region may considerably influence the diagnostics of the plasma emission measure. The cross-sectional area of the loops is expected to depend on the temperature and pressure, and might be sensitive to the heating rate. Aims. The approach here is to study the area response to slow changes in the coronal heating rate, and check the current interpretation in terms of steady heating models. Methods. We study the area response with a time-dependent 2D magnetohydrodynamic (MHD) loop model, including the description of the expanding magnetic field, coronal heating and losses by thermal conduction, and radiation from optically thin plasma. We run a simulation for a loop 50 Mm long and quasi-statically heated to about 4 millikelvin. Results. We find that the area can change substantially with the quasi-steady heating rate, e.g., by approx. 40% at 0.5 millikelvin as the loop temperature varies between 1 millikelvin and 4 millikelvin, and, therefore, affects the interpretation of the differential emission measure vs. temperature (DEM(T)) curves.

Published
2014
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9. Simultaneous Kepler/K2 and XMM-Newton observations of superflares in the Pleiades

Author

Guarcello, M. G., primary, Micela, G., additional, Sciortino, S., additional, López-Santiago, J., additional, Argiroffi, C., additional, Reale, F., additional, Flaccomio, E., additional, Alvarado-Gómez, J. D., additional, Antoniou, V., additional, Drake, J. J., additional, Pillitteri, I., additional, Rebull, L. M., additional, and Stauffer, J., additional

Published
2019
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49. Thermal structure of a hot non-flaring corona from Hinode/EIS

Author

Fabio Reale, Paola Testa, G. Del Zanna, A. Petralia, Petralia, A, Reale, F, Testa, P, and Del Zanna, G

Subjects
Physics, Sun: corona, Sun: UV radiation, Sun: X-rays, gamma rays, techniques: spectroscopic, techniques: imaging spectroscopy, Line-of-sight, Sun: corona, Extreme ultraviolet lithography, Techniques: spectroscopic, FOS: Physical sciences, Astronomy and Astrophysics, Thermal distribution, Plasma, Astrophysics, Astronomy and Astrophysic, Sun: UV radiation, Imaging data, Corona, Settore FIS/05 - Astronomia E Astrofisica, Astrophysics - Solar and Stellar Astrophysics, Sun: X-rays, gamma ray, Space and Planetary Science, Thermal, Techniques: imaging spectroscopy, Solar and Stellar Astrophysics (astro-ph.SR), Line (formation)
Abstract

In previous studies a very hot plasma component has been diagnosed in solar active regions through the images in three different narrow-band channels of SDO/AIA. This diagnostic from EUV imaging data has also been supported by the matching morphology of the emission in the hot Ca XVII line, as observed with Hinode/EIS. This evidence is debated because of unknown distribution of the emission measure along the line of sight. Here we investigate in detail the thermal distribution of one of such regions using EUV spectroscopic data. In an active region observed with SDO/AIA, Hinode/EIS and XRT, we select a subregion with a very hot plasma component and another cooler one for comparison. The average spectrum is extracted for both, and 14 intense lines are selected for analysis, that probe the 5.5 < log T < 7 temperature range uniformly. From these lines the emission measure distributions are reconstructed with the MCMC method. Results are cross-checked with comparison of the two subregions, with a different inversion method, with the morphology of the images, and with the addition of fluxes measured with from narrow and broad-band imagers. We find that, whereas the cool region has a flat and featureless distribution that drops at temperature log T >= 6.3, the distribution of the hot region shows a well-defined peak at log T = 6.6 and gradually decreasing trends on both sides, thus supporting the very hot nature of the hot component diagnosed with imagers. The other cross-checks are consistent with this result. This study provides a completion of the analysis of active region components, and the resulting scenario supports the presence of a minor very hot plasma component in the core, with temperatures log T > 6.6., 12 pages, 8 figures, accepted for publication

Published
2014

50. X-ray emitting hot plasma in solar active regions observed by the SphinX spectrometer

Author

Magdalena Gryciuk, Piotr Podgorski, Szymon Gburek, Fabio Reale, S. Terzo, Alfonso Collura, Miroslaw Kowalinski, Marco Barbera, Janusz Sylwester, Marco Miceli, Miceli, M, Reale, F, Gburek, S, Terzo, S, Barbera, M, Collura, A, Sylwester, J, Kowalinski, M, Podgorski, P, and Gryciuk, M

Subjects
Physics, 010504 meteorology & atmospheric sciences, Spectrometer, X-ray, Bremsstrahlung, Astronomy and Astrophysics, Plasma, Astrophysics, 01 natural sciences, Corona, Spectral line, Sun: corona, methods: observational, techniques: spectroscopic, Stars, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Calibration, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

Aims. The detection of very hot plasma in the quiescent corona is important for diagnosing heating mechanisms. The presence and the amount of such hot plasma is currently debated. The SphinX instrument on-board the CORONAS-PHOTON mission is sensitive to X-ray emission of energies well above 1 keV and provides the opportunity to detect the hot plasma component. Methods. We analysed the X-ray spectra of the solar corona collected by the SphinX spectrometer in May 2009 (when two active regions were present). We modelled the spectrum extracted from the whole Sun over a time window of 17 days in the 1.34− 7k eV energy band by adopting the latest release of the APED database. Results. The SphinX broadband spectrum cannot be modelled by a single isothermal component of optically thin plasma and two components are necessary. In particular, the high statistical significance of the count rates and the accurate calibration of the spectrometer allowed us to detect a very hot component at ∼7 million K with an emission measure of ∼2.7 × 10 44 cm −3 . The X-ray emission from the hot plasma dominates the solar X-ray spectrum above 4 keV. We checked that this hot component is invariably present in both the high and low emission regimes, i.e. even excluding resolvable microflares. We also present and discuss the possibility of a non-thermal origin (which would be compatible with a weak contribution from thick-target bremsstrahlung) for this hard emission component. Conclusions. Our results support the nanoflare scenario and might confirm that a minor flaring activity is ever-present in the quiescent corona, as also inferred for the coronae of other stars.

Published
2012

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