The Genesis Onboard CME Identification

With the Genesis mission, for the first time a satellite autonomously and in real time characterized the nature of the solar wind. Measurements from the Genesis Ion Monitor (GIM) and the Genesis Electron Monitor (GEM) were passed as input to a flight software algorithm. That algorithm categorized the solar wind as coronal hole-related fast wind, interstream slow wind, or coronal mass ejection (CME). The spacecraft then exposed the associated regime-specific collector array, thereby gathering solar wind samples sorted by flow type. Because CME composition is expected to be the most highly fractionated and variable relative to the sun, we sought to avoid contaminating the coronal hole and interstream collections with CME solar wind. The algorithm design was biased in favor of easy entry into, and difficult exit from, the CME regime. As a result, the fraction of observations attributed to CME by Genesis, 23%, is likely an over-estimate of the fraction of solar wind that was in fact CME-related during the mission. In the approximately 28 months of operation, Genesis triggered CME collection 108 times. A preliminary inspection suggests that at least 20 of those autonomous CME detections were questionable. We will present a comparison of the real-time autonomous CME identifications with a retrospective analysis. Our report will give particular emphasis to comparing the bidirectional electron streaming detected on-board with that identified in post-mission analysis, and we will report the fraction of probable closed-loop field observed.