Feasibility study of probing the high energy end of the primary cosmic electron spectrum by detecting geo-synchrotron X-rays

TL;DR

This study evaluates the potential of detecting high-energy cosmic electrons via geo-synchrotron X-rays using a satellite-based detector, highlighting the method's feasibility and limitations for identifying TeV electrons.

Contribution

It demonstrates the feasibility of using geo-synchrotron X-ray detection to observe TeV cosmic electrons from space, offering a novel approach to high-energy cosmic ray studies.

Findings

Detection of TeV electrons is feasible with sufficient exposure.

The method can confirm the existence of high-energy electrons if flux levels are as predicted.

Precise energy spectrum measurement remains challenging.

Abstract

Based on tests of a tentative detector for observing geo-synchrotron hard X-rays generated by primary electrons, we study the feasibility of probing cosmic electrons above a few TeV to over 10 TeV. Such high energy electrons are expected to give proof of sources near the Earth (e.g. supernova remnants such as Vela: age < ~10^5 years located within <~1kpc). The idea itself is rather old; a high energy electron emits synchrotron X-rays successively in the geomagnetic field and thus gives several X-rays aligned on a meter scale. This feature is a clue to overcome the background problem encountered in other traditional observation methods. We critically examine the feasibility of this approach assuming a satellite altitudes observation, and find that it is difficult to derive a precise energy spectrum of electrons but is possible to get a clear signal of the existence of several TeV electrons if the flux is comparable to the level predicted by a class of plausible models. For such observations, an exposure >1 m^2year would be needed. It would be attractive to incorporate the present scheme in the gamma-ray burst observations.