Inversions of Flaring Radio Emissions

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
Kleins GS approxi-mation for isotropic electron
distribu-tion
9
(No Transcript)
10
10 March 2001
11
Exact GS formulae
12
Turbulence parameter a2 10-7
13
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
  of information 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.