Multi-Spacecraft Bowshock Database at NSSDC

By Natalia Papitashvili, Mona Kessel, Joe King

NSSDC's bowshock crossings database at http://nssdc.gsfc.nasa.gov/ftphelper/bowshock.html has been significantly improved recently by adding data from a number of spacecraft and enhancing its web-based interactive interface. The database now includes the bowshock crossings made by the following spacecraft: IMP-8 (1992-2000), Geotail (1995-1997), Magion (1996-1997), and Cluster (2001-2002). Time coverage for each, except Magion, will be further extended.

Each record in the database contains the time and location of the actual crossing, the observed upstream interplanetary magnetic field (IMF) and solar wind plasma parameters and the downstream plasma density (IMP only), as well as several NSSDC-computed parameters (flow pressure, sonic and Alfvenic Mach numbers, beta, etc.).  The record's format is the same for all spacecraft, although some fields have meaningful values only for IMP.

The new web-based interactive interface identified above allows users to select any combination of spacecraft, time span, and/or ranges for any parameters in the database. We have also added output sorting capabilities by date and time or by any user-selected parameter.  The underlying data are accessible as annual ASCII files from ftp://nssdcftp.gsfc.nasa.gov/spacecraft_data/bowshock_crossings/.

These data and interfaces allow the user to accomplish several scientific tasks, for example, (1) find nearly simultaneous crossings; (2) specify the crossings for specific IMF and solar wind conditions; (3) find the crossings in the certain regions of the bowshock (e.g., dayside, flanks, etc).

The IMP-8 basic shock identification and specification of the upstream observables were done by the members of the IMP-8 magnetometer group at Goddard (A. Szabo, J. Merka, T. Narock) and of the MIT's IMP-8 plasma group (K. Paularena, J. Richardson, L. Finck). The Magion-4 (Interball- Tail's sub-satellite) bowshock crossings were supplied by J. Safrankova and Z. Nemecek (Charles University, Prague, Czech Rep.).  The Geotail and Cluster crossings were identified by R. Kessel (GSFC).