The Abundance of Deuterium and He3 in the Solar Wind

TL;DR

This paper proposes a method to measure deuterium abundance in the solar wind using a specialized instrument, aiming to understand its variation and contribution to solar and stellar processes.

Contribution

It introduces a novel instrument design for detecting deuterium in the solar wind and outlines a project to monitor its abundance over several years.

Findings

Instrument successfully tested in space in 1975

Method enables detection of deuterium via alpha particle production

Potential to monitor deuterium evolution during solar activity

Abstract

The relative abundance of deuterium (D) in the solar atmosphere is not known. D is not only destroyed in stars, it is also synthesized in the atmospheres of active stars (Prodanovic & Fields 2003). In several cases, production of D in the sun has been detected when solar flares occur, using both energetic particle measurements (Anglin 1975) and by detection of 2.223 MeV gamma rays emitted by D (Terekhov et al. 1996; Shih et al. 2009). We describe a project to measure the abundance of deuterium in the solar wind, and to monitor its evolution during a several-year period. The instrument consists of two grids, a tritium target, and semiconductor particle detectors. The grids, which are hemispherical and concentric, accelerate the incident solar wind ions using a potential difference on the order of ~80 to 100 kV and concentrate the ions on the tritium target. A fraction of the solar wind deuterons thus accelerated interact with the target to produce 3.6 MeV alpha particles, some of which are recorded by adjacent semiconductor detectors. A similar instrument was successfully tested in space in 1975 in order to observe positive auroral ions in a hydrogen aurora.