X-Ray Polarization of Solar Flares Measured with Rhessi

Abstract

The degree of linear polarization in solar flares has not yet been precisely determined despite multiple attempts to measure it with different missions. The high energy range in particular has very rarely been explored, due to its greater instrumental difficulties. We approached the subject using the Reuven Ramaty High Energy Spectroscopic Imager (RHESSI) satellite to study 6 X-class and 1 M-class flares in the energy range between 100 keV and 350 keV. Using RHESSI as a polarimeter requires the application of strict cuts to the event list in order to extract those photons that are Compton scattered between two detectors. Our measurements show polarization values between 2% and 54%, with errors ranging from 10% to 26% in 1 sigma level. In view of the large uncertainties in both the magnitude and direction of the polarization vector, the results can only reject source models with extreme properties.

arXiv comment26 pages, 11 figures, accepted for publication by Solar Physics

References in corpus (5)

• Polarization of the prompt gamma-ray emission from the gamma-ray burst of 6 December 2002
• Re-Analysis of Polarization in the Gamma-ray flux of GRB 021206
• Gamma-Ray Burst Polarization: Limits from RHESSI Measurements
• RHESSI as a Hard X-Ray Polarimeter
• Gamma-Ray Polarimetry of Two X-Class Solar Flares

Cited by in corpus (16)

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• Spatially resolved hard X-ray polarization in solar flares: effects of Compton scattering and bremsstrahlung
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• Measurements of electron anisotropy in solar flares using albedo with RHESSI X-ray data
• The influence of albedo on the size of hard X-ray flare sources
• The gas pixel detector as a solar X-ray polarimeter and imager
• Measuring X-ray anisotropy in solar flares. Prospective stereoscopic capabilities of STIX and MiSolFA
• Gamma Ray polarimetry; a new window for the non-thermal Universe
• Instrumentation and Future Missions in the Upcoming Era of X-Ray Polarimetry
• Gamma-Ray Polarimetry
• The soft X-ray spectrometer polarimeter SolpeX
• Hard X-ray Polarimetry -- An overview of the method, science drivers and recent findings
• Spectral performance of single-channel plastic and GAGG scintillator bars of the CUbesat Solar Polarimeter (CUSP)