Soft x-ray solar polarimeter-spectrometer

We present an innovative soft X-ray polarimeter and spectrometer SOLPEX, the instrument to be mounted aboard the International Space Station (ISS) in 2015/2016. The SOLPEX will be composed of three individual measuring units: the soft X-ray polarimeter with 1-2% linear polarization detection limit, a fast-rotating drum X-ray spectrometer with very high time resolution (0.1s) and a simple pin-hole soft X-ray imager-spectrometer with moderate spatial (~20arcsec), spectral (0.5 keV) and high time resolution (0.1s). This set of instruments will provide unique opportunity to complement the efforts to reliably measure the X-ray polarization and contribute towards understanding the physics of solar flares. The standard flare model states that electrons are being accelerated in specific regions of the corona at or near magnetic reconnection site and then propagate along reconnected magnetic field lines toward the atmospheric denser layers. There, they are decelerated and lose their energy mainly through the bremsstrahlung process. Deposited energy is readily converted to directed evaporation of the plasma to be detected through the Doppler-shifted emission lines in extreme ultraviolet and soft X-ray spectral ranges Due to highly anisotropic character of impulsive phase electron beams, resulting emission is expected to be polarized. Both these processes: bremsstrahlung emission of supposedly polarized X-ray flux and accompanying plasma evaporation velocities are to be simultaneously observed by the proposed SOLPEX instruments.

[1]  J. Skibo,et al.  Is the High-Energy Emission from Centaurus A Compton-Scattered Jet Radiation? , 1994, astro-ph/9402047.

[2]  Robert Novick,et al.  Polarization evidence for the isotropy of electrons responsible for the production of 5--20 keV X-rays in solar flares , 1984 .

[3]  V. D. Ivanov,et al.  On the polarization of the emission of X-ray solar flares , 1970 .

[4]  E. Haug.  Electron impact polarization of X-ray lines from hydrogen-like ions during solar flares , 1981 .

[5]  A. Bogomolov,et al.  Polarization, temporal, and spectral parameters of solar flare hard X-rays as measured by the SPR-N instrument onboard the CORONAS-F satellite , 2006 .

[6]  K. Zioutas,et al.  A proposal for solar axion detection via Bragg scattering , 1994 .

[7]  R. Novick,et al.  The X-ray polarization of the Cygnus sources , 1980 .

[8]  M. McConnell,et al.  Status and Future Prospects for -ray Polarimetry , 2005, astro-ph/0508315.

[9]  R. Sunyaev,et al.  Comptonization of low-frequency radiation in accretion disks: angular distribution and polarization of hard radiation , 1985 .

[10]  W. Hajdas,et al.  X-Ray Polarization of Solar Flares Measured with Rhessi , 2006, astro-ph/0609778.

[11]  W. Steffen,et al.  The polarization of X-ray emission of some solar flares in July 1974 , 1976 .

[12]  V. D. Ivanov,et al.  New measurements of the polarization of X-ray solar flares , 1972 .

[13]  V. D. Ivanov,et al.  Preliminary interpretation of the polarization measurements performed on ‘Intercosmos-4’ during three X-ray solar flares , 1972 .

[14]  F. Fárník,et al.  X-ray Flare Spectra from the DIOGENESS Spectrometer and Its Concept Applied to ChemiX on the Interhelioprobe Spacecraft , 2014, 1411.0850.

[15]  Mark L. McConnell,et al.  Hard x-ray polarimetry with the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) , 2003, SPIE Astronomical Telescopes + Instrumentation.

[16]  A. Kuznetsov,et al.  Diagnostics of energetic electrons with anisotropic distributions in solar flares , 2010 .

[17]  J. C. Brown,et al.  The polarization and directivity of solar-flare hard X-ray bremsstrahlung from a thermal source , 1980 .

[18]  Eduard Kontar,et al.  Spatially resolved hard X-ray polarization in solar flares: effects of Compton scattering and bremsstrahlung , 2011, 1110.4993.

[19]  K. Long,et al.  A precision measurement of the X-ray polarization of the Crab Nebula without pulsar contamination. , 1978 .

[20]  R. Kopp,et al.  Magnetic reconnection in the corona and the loop prominence phenomenon , 1976 .

[21]  B. Dennis,et al.  VELOCITY CHARACTERISTICS OF EVAPORATED PLASMA USING HINODE/EUV IMAGING SPECTROMETER , 2009, 0905.1669.

[22]  Werner M. Neupert,et al.  Polarization results of solar X-rays from OSO-7 , 1974 .

[23]  E. Kalemci,et al.  Gamma-Ray Polarimetry of Two X-Class Solar Flares , 2005, astro-ph/0510588.