Software Development for Jointly Analyzing Thermal-Ion Measurements from Multiple In-Situ Instruments

Tuesday, 16 December 2014
Bennett Maruca, University of California Berkeley, Berkeley, CA, United States, Michael Louis Stevens, Smithsonian Astrophysics Observatory, Cambridge, MA, United States, Justin Christophe Kasper, University of Michigan, Ann Arbor, MI, United States and Kelly E Korreck, Smithsonian Observatory, Cambridge, MA, United States
The Wind spacecraft provides high-quality, in-situ measurements of the solar wind's thermal ions with two separate instruments -- an electrostatic analyzer and a pair of Faraday cups. Each instrument's raw measurements must be processed to derive values for bulk parameters (e.g., densities, velocities, and temperatures). Until now, this analysis has always been carried out independently for each instrument. We report on our ongoing development of new software, dubbed "Janus," that will, for the first time, jointly analyze measurements from these two instruments. By drawing on their unique strengths, Janus will produce higher-quality data on solar-wind ions than an analysis of measurements from either instrument individually could. While Janus on its own will be an asset to the heliophysics community (especially for the study of CME's, CIR's, and other transient phenomena), it will also serve as an important case study for Solar Probe Plus (SPP), which will similarly have both a Faraday cup and an electrostatic analyzer for measuring thermal ions. A joint analysis of measurements from these SPP instruments will be especially important since, unlike their counterparts on Wind, their fields of view will only slightly overlap. SPP is expected to frequently encounter periods during which its two ion instruments together will have strong coverage of the incoming particles but separately will not.