Other RHESSI
Web Sites

Radio/X-ray observations of flares

bulletVariability in time and space of the characteristics of the accelerated particles in the course of flare development.
bulletHow are particles accelerated ? In which environment ?
bulletMultiwavelength studies performed with the Nançay Radioheliograph (NRH) in past version
bulletVariation of electron spectra and of e/p ratio on time scales of 10s together with variability in space as seen in radio or Ha .

Characteristics of the energetic particles and magnetic structures at ¹ scales involved in the flare development using HESSI and new NRH capabilities

2 May 1998 Flare/halo CME

bullet GOES X disk flare associated with initial stage of a halo CME (Pohjolainen et al…submitted)
bullet New radio sources appear during the « flash » phase of the flare (sudden increase of the emission) together with a sudden extension of emission towards high frequencies.
bullet Simultaneous jump of HXT source positions at 33-53 keV (sites of non-thermal energy releases). Spectral evolution ?
bullet Radio images provide tools to identify the loop systems that participate to the CME 
bullet Radio images provide tools to understand the effects of EIT/H a waves in destabilizing the coronal field.

27 November 1997 Flare

bullet GOES X2 flare associated with production of decimetric/metric type II burst starting at high frequencies ( 400 MHz)
bullet Close temporal and spatial relationship between the first signature of the type II burst and the arrival of fast moving plasma blobs at coronal heights (blast wave). ( Klein et al 1999)
bullet Earlier flare development
bullet X-ray/ g -ray spectral evolution simultaneously with the onset of the shock wave emission ?(to be further checked with OSSE observations)
bullet Sudden appearance of a new radio source simultaneously with the sharp X-ray/ g -ray spike and just before the onset of the type II burst…
bullet Interpretation … ?

Nançay Radioheliograph

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bullet 2d and 2x1d images of the solar corona at 5 to 10 frequencies between 150 and 450 MHz
bullet time resolution : 10 im/s (for 5 frequencies)
bullet spatial resolution : from 0.6 to 6 arcmin depending on frequency and direction
bullet polarization : Stockes I and V
bullet observing time : 7.5h around 12h
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bullet available on line :   http://mesola.obspm.fr
bullet data up to one image per 10 seconds
bullet + soft in solar soft (NRH branch)
bullet next step: direct access in Hessi branch
bullet quick look of radio flares associated with HESSI flares?

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Gordon.D.Holman@nasa.gov

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This site last updated November 10, 2008.