80 likes | 101 Views
Explore the far infrared emission of solar flares and how charged particles are accelerated to high energies. Analyze energy conversion processes and examine particle acceleration mechanisms in the Sun. Discover unexplored solar electromagnetic emission ranges and investigate physical processes like thermal emission, white light continuum excitation, and energetic positrons from nuclear reactions.
E N D
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
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)
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 !
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
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
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)
(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 ?
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 ?