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Far infrared emission of solar flares

Visions for infrared astronomy, Paris, 20 March 2006. Far infrared emission of solar flares. Observatoire de Paris, LESIA G. Trottet, K.-L. Klein , G. Molodij, A. Sémery and the DESIR Team. Observatoire de Meudon -LESIA, ludwig.klein@obspm.fr , +33 1 45 07 77 61.

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Far infrared emission of solar flares

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  1. Visions for infrared astronomy, Paris, 20 March 2006 Far infrared emission of solar flares Observatoire de Paris, LESIA G. Trottet, K.-L. Klein, G. Molodij, A. Sémery and the DESIR Team Observatoire de Meudon -LESIA,ludwig.klein@obspm.fr, +33 1 45 07 77 61

  2. Energetic particles in the universe • 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 ? Solar and Heliospheric Observatory / EIT (ESA/NASA) Compton Gamma Ray Observatory / EGRET (NASA)

  3. SST, KOSMA synchrotron models Solar black body (entire disk) m-dm- White light continuum log(flux density [W m-2 Hz-1]) -25 -15 -20 Hard X Thermal models -30 UV, EUV, Soft X -35  9 12 15 18 21 log(frequency [Hz]) ? cm-mm- Visible light Radio From mm- to visible light : 3 orders of magnitude unexplored !

  4. 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 ??? Trottet et al. 2002 A&A Relativistic electrons at the Sun (1) Univ. Mackenzie Sao Paulo

  5. Decreasing gyrosynchrotron spectrum  200 GHz Spectral upturn  > 200 GHz (KOSMA1)- why ? Luethi et al. 2004 A&A A more complex spectrum: flare on 28 Oct 2003 • 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. p e+  ±  e ± 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) B=400 G p,  > 200 MeV/nucléon  0, +, - B Lingenfelter & Ramaty 1967, Planet. Spa. Sci. 15, 1303 2 (70 MeV)

  7.  (DESIR) Temperature 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 ?

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