Time structure of the X-ray emission of thermal solar flares |
| |
| Authors: | E M Sklyarova Yu E Charikov |
| |
| Institution: | 1. Ioffe Physical and Technical Institute, Russian Academy of Sciences, Polytekhnicheskaya ul. 26, St. Petersburg, 194021, Russia
|
| |
| Abstract: | Based on observations of electromagnetic radiation, a concept of thermal solar flares has been proposed. The absence of hard X-ray emission implies no accelerated electrons. This fact is the basis of the proposed concept of thermal flares. Since the acceleration rate should not exceed the electron energy loss rate, plasma density in the acceleration range must be at least 1011 cm?3. The temperature of plasma emitting in the soft X-ray range is of the order of 107 K. In the simplified problem of heated plasma hydrodynamics, we calculated the temperature profiles and their changes over time and by coordinate. The emission measure values determined from observations of the soft X-ray emission of flares is of the order of 1045 cm?3. The geometry of the source is an axial symmetric straight cylinder with a section of 1016 cm2 and an axial coordinate determined by the depth of plasma heating. Time profiles of soft X-ray emission were calculated for different sources of plasma heating, which were simulated using the Gaussian distribution law with respect to the coordinate and time. We have considered two modes of plasma heating: single (in time) and multipulse modes with different pulse intervals. The dynamics of plasma heating and cooling was shown to control the experimentally observed time profiles of soft X-ray emission. A comparison of numerical results with observational data allows us to confirm the implications of the proposed concept of thermal flares and, in addition, to perform diagnostics of plasma parameters in the emission source. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
