The x-ray detectability of electron beams escaping from the sun

TL;DR

This study assesses the potential for detecting and characterizing electron beams escaping the sun via their nonthermal X-ray emission, identifying optimal conditions and instrumentation capabilities for observation.

Contribution

It demonstrates that large interplanetary electron beams can be detected with current X-ray instruments and outlines the observational requirements for effective characterization.

Findings

Large electron beams (>=10^35 electrons) are detectable in X-rays.

Imaging capability is crucial for proper beam characterization.

Coronal soft X-ray jets may result from local heating by electron beams.

Abstract

We study the detectability and characterization of electron beams as they leave their acceleration site in the low corona toward interplanetary space through their nonthermal X-ray bremsstrahlung emission. We demonstrate that the largest interplanetary electron beams (>=10^35 electrons above 10 keV) can be detected in X-rays with current and future instrumentation, such as RHESSI or the X-Ray Telescope (XRT) onboard Hinode.We make a list of optimal observing conditions and beam characteristics. Amongst others, good imaging (as opposed to mere localization or detection in spatially integrated data) is required for proper characterization, putting the requirement on the number of escaping electrons (above 10 keV) to >= 3 \times 10^36 for RHESSI, >=3 \times 10^35 for Hinode/XRT, and >=10^33 electrons for the FOXSI sounding rocket scheduled to fly in 2011. Moreover, we have found that simple modeling hints at the possibility that coronal soft X-ray jets could be the result of local heating by propagating electron beams.