Sub - terahertz , microwaves and high energy emissions during the 6 December 2006 flare , at 18 : 40 UT

The presence of a solar burst spectral component with flux density increasing with frequency in the sub-terahertz range, spectrally separated from the well-known microwave spectral component, bring new possibilities to explore the flaring physical processes, both observational and theoretical. The solar event of 6 December 2006, starting at about 18:30 UT, exhibited a particularly welldefined double spectral structure, with the sub-THz spectral component detected at 212 and 405 GHz by SST and microwaves (1-18 GHz) observed by the Owens Valley Solar Array (OVSA). Emissions obtained by instruments in satellites are discussed with emphasis to ultra-violet (UV) obtained by the Transition Region And Coronal Explorer (TRACE), soft X-rays from the Geostationary Operational Environmental Satellites (GOES) and Xand γ-rays from the Ramaty High Energy Solar Spectroscopic Imager (RHESSI). The sub-THz impulsive component had its closer temporal counterpart only in the higher energy Xand γ-rays ranges. The spatial positions of the centers of emission at 212 GHz for the first flux enhancement were clearly displaced by more than one arcminute from positions at the following phases. The observed sub-THz fluxes and burst source plasma parameters were found difficult to be reconciled to a purely thermal emission component. We discuss possible mechanisms to explain the double spectral components at microwaves and in the THz ranges. 1 Centro de Rádio-Astronomia e Astrof́ısica Mackenzie, Escola de Engenharia, Universidade Presbiteriana Mackenzie, Rua Consolação 896, 01302-907 São Paulo, SP, Brazil. email:[email protected] 2 Centro de Componentes Semicondutores,Universidade Estadual de Campinas, Campinas, SP, Brazil. 3 LESIA, Observatoire de Paris-Meudon, Meudon, France. 4 Space Sciences Laboratory, University of California Berkeley, Berkeley, CA, USA. 5 Complejo Astronómico El Leoncito, San Juan, Argentina. SOLA: paper_v20081215.tex; 17 December 2008; 1:54; p. 1