Search Coil and Fluxgate Data Merging on MMS: Examples on Dipolarization Event Cases

Abstract:

The instrument suite of MMS mission includes one search coil and two fluxgate magnetometers on each observatory and can therefore provide the possibility to study events that cross the sensitive frequency range of both instrument types. It is therefore desirable to have a common merged data product that combines the best parts of both instruments. Extensive ground based test measurements have been performed to identify the properties of the instruments. New models for compensating time and frequency properties were created and the difference to existing calibrations is analyzed. Considerations for application as well as signal processing constraints are discussed and the resulting method is applied on data from the mission. Dipolarization events can serve as suitable example, since they contain a variety of disturbances with different characteristic scales: transient filamentary properties, sharp fronts, reconfiguration of the current sheet, wave signatures on kinetic as well as fluid scales, thus requiring highest sensitivity data in a wide frequency range. We show these different signatures relevant to the dipolarization events based on the analysis of these newly produced data.