Far infrared emission of solar flares

1
Far infrared emission of solar flares
Visions for infrared astronomy, Paris, 20 March
2006

• Observatoire de Paris, LESIA
• G. Trottet, K.-L. Klein, G. Molodij, A. Sémery
• and the DESIR Team

Observatoire de Meudon -LESIA, ludwig.klein_at_obspm.
fr, 33 1 45 07 77 61
2
Energetic particles in the universe
Solar and Heliospheric Observatory / EIT
(ESA/NASA)
Compton Gamma Ray Observatory / EGRET (NASA)

• Supernova remnants, active galactic nuclei and
  the Sun
• How are charged particles accelerated to
  relativistic energies ? What is their part in
  energy conversion w/r to heating large-scale
  mass motion ?

3
?
cm-mm-?
Visible light
Radio
From mm-? to visible light 3 orders of
magnitude unexplored !
4
Relativistic electrons at the Sun

• Solar radio burst impulsive particle
  acceleration on second - time scale
• ?212 GHz (SST1) synchrotron emission from
  relativistic e- ? ? ?2 ?ce
• Up to which energies ? How rapidly ? How often ?
  ? Which mechanism ???

(1) Univ. Mackenzie Sao Paulo
5
A more complex spectrum flare on 28 Oct 2003

• Decreasing gyrosynchrotron spectrum ? 200 GHz
• Spectral upturn ? gt 200 GHz (KOSMA1)- why ?

• thermal ? If so, not from corona !
• opt. thin synch. emission, rising energy spectrum
  dense environment ?

(1) Univ. Cologne Bern
Trottet et al. in preparation
6
Synchrotron emission from positrons
opt. thin synchrotron
Radio power at Earth 10-22 W m-2 Hz-1
DESIR
Razin suppressed synchrotron
SST, KOSMA
Frequency / electron cyclotron frequency
p (200 MeV)
e (50 MeV)
B400 G
??B??
p, ? gt 200 MeV/nucléon ? ?0, ?, ?-
Lingenfelter Ramaty 1967, Planet. Spa. Sci.
15, 1303
2? (70 MeV)
7
Energy transport in solar flares

• FIR continuum
• Chromosphere T-minimum
• Radiative transport easier than optical lines
• Sub-second time resolution

• Flare energy released in the corona
• Transport to the low atmosphere (? visible
  emission) by conduction ? Particle beams ? Which
  particles ?

8
SMESE a french-chinese ?-satellite project

• A package of complementary instruments for a
  micro-satellite mission (CNES / Myriade 2012 ?)
• - Ly ? coronagraph disk imager (IAS Orsay)
• - HXR gamma-ray spectrograph (10 keV-600 MeV
  Purple Mountain Nanjing University)
• - FIR photometry and source localisation (DESIR
  Paris Observatory)

• An unexplored spectral range of solar EM
  emissions.
• The most energetic electrons the Sun is able to
  accelerate, and the most stringent test of
  acceleration models.
• Poorly explored physical processes thermal
  emission and energy transport excitation of
  white light continuum energetic positrons from
  nuclear reactions ?