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RHESSI observations of the M 1.0 solar flare on 22 October 2002 A. Berlicki 1,2 , B. Schmieder 1 , N. Vilmer 1 , G. Aulanier 1 1) Observatoire de Paris, Section de Meudon, LESIA, FRANCE 2) Astronomical Institute of the Wroc ł aw University, POLAND. The aim of the work:
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RHESSI observations of the M 1.0solar flare on 22 October 2002A. Berlicki1,2, B. Schmieder 1, N. Vilmer 1, G. Aulanier 11) Observatoire de Paris, Section de Meudon, LESIA, FRANCE2) Astronomical Institute of the Wrocław University, POLAND
The aim of the work: Why the flare emission in cool chomospheric lines (H, Ca lines) is observed for a long time during the late phase of solar flares ? What kind of heating mechanism is effective during the gradual phase of solar flares ? * Small flux of non-thermal electrons ? * Thermal conduction ? * Radiative heating by soft X-rays ? We try to explain if the non-thermal component in X-ray emission could be present during the gradual phase of solar flares.
MDI - cont. BBSO - H-alpha
Ha flare (VTT) + RHESSI 22 oct 2002 ICONT (Na D1,THEMIS) HXR (RHESSI) TRACE 195 ang. BLONG (NaD1, THEMIS)
Thermal and non-thermal component during the gradual phase a) Thermal energy of plasma: b) Energy contained in the non-thermal electrons (thin target model): (Hudson et al. 1978, Sol. Phys. 60, 137) (for ECUT-OFF = 10 keV) - power-law index B(x,y) – beta function 10 – X-ray flux at 10 keV [photons cm-2 s-1 keV-1]
Thermal Ethand non-thermal Enthenergy contained in the flare of October 22, 2002. ? ? ?
Conclusions: • During the analysed period the thermal energy is dominant, • Non-thermal component provide a marginal input to the total • energy but it is necessary to explain the spectra between • 10 and 20 keV, • ? ? ? • * Thin or thick target, • * Distinguish between thermal and non-thermal emission at • low energies, • * Relation between Ecut-off and the energy contained in non-thermal • electrons – very sensitive !