1 / 13

Inversions of Flaring Radio Emissions

Inversions of Flaring Radio Emissions. Gregory D. Fleishman. Relevant Recent Discoveries. 1. Pitch-angle anisotropy : - loop-top radio sources (NoRH) - variations of polarization (NoRH) - spectral variations (OVSA) 2. Dense flare environment - coronal loop HXR sources (RHESSI)

pelham
Download Presentation

Inversions of Flaring Radio Emissions

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Inversions of Flaring Radio Emissions . Gregory D. Fleishman

  2. Relevant Recent Discoveries 1.Pitch-angle anisotropy: - loop-top radio sources (NoRH) - variations of polarization (NoRH) - spectral variations (OVSA) 2.Dense flare environment - coronal loop HXR sources (RHESSI) - Razin effect in many radio bursts (OVSA) - resonant transition radiation in 10% of the bursts (OVSA) - cold dense flares (OVSA+ NoRH)

  3. Implication for the radio burst modeling: take into account 1.For nonthermal electrons: - Anisotropic acceleration/injection, - Anisotropic transport effects, - Isotropisation due to collisions and wave-particle interactions, - Coronal losses of fast electrons 2.For emission generation and transport: - Free-free absorption - Razin suppression of the gyrosynchrotron emission - Source inhomogeneity - Other emission procersses (RTR, ECM…)

  4. Uniform, optically thin source with strong Razin-effect Simplfied model fitting Sequence of fitted spectra Derived parameters vs time

  5. Almost No SXRs! 24 October 2001 AR 9672

  6. 3 NoRP light curves 17 GHz 2 4 35 GHz Images obtained for moments 1-4 1 9.4 GHz

  7. NoRH images 1 2 3 4 17 GHz I 17 GHz V 34 GHz I

  8. Klein’s GS approxi-mation for isotropic electron distribu-tion

  9. 10 March 2001

  10. Exact GS formulae

  11. Turbulence parameter a=2 * 10-7

  12. CONCLUSIONS 1.A number of recent discoveries calls for new, more detailed and sophisticated models of radio emission from solar flares. 2.Nonthermal radio emission depends not only on the magnetic field and energy distribution of fast electrons, but also on the pitch-angle anisotropy, background plasma density and temperature, source structure, and the turbulence level, thus, potentially it is a valuable source ofinformation of the corresponding physical parameters and related processes. 3.The development of new reliable models and fitting algorithms is of primary importance and urgently needed to fully exploit the potential diagnostic capabilities of the planned project of a new solar dedicated radio instrument, Frequency Agile Solar Radiotelescope.

More Related