Generation of plasma boundary datasets for CAA Tiera Laitinen Finnish Meteorological Institute

An overview of the project Purpose Timeline Basic spesifications The boundaries Neutral sheet Radiation belt edge Magnetopause Bow shock Make your comments immediately, do not wait until the end.

Generate datasets of boundary crossings identified from the Cluster data. Time span: Feb 2001 to Dec Data provided to the users through CAA. A Matlab code for semi-automated boundary recognition will be produced for the work. Automated boundary search by a simple numerical criterion Data visualisation Easy manual correction of the boundary crossing time.

Nov 2010 Definition of boundary search criteria Development of GUI tool Dec 2010 Jan 2011 Development of automated search algorithms Feb 2011 Finalization and testing of search code Definition of quality flags March 2011 ”Dress rehearsal”: boundaries 2001 Several scientists cross-check that they agree on results. Apr – Oct 2011 Production of boundary datasets 2001–2008. Project ends: November 2011.

Spin-resolution data from CAA will be used. One outbound and one inbound boundary crossing per orbit will be determined. For neutral sheet, one crossing per orbit. A quality flag indicating the type of crossing will be included: e.g. single / multiple / unclear. caveat remarks written when necessary.

In the region X 5, |Z| < R. Determined from the sign change of the radial component of the magnetic field, B r = 0. Coordinate system independent definition. Near the flanks the field is more radial than X-aligned. In case of flapping current sheet (multiple crossings): We fit a Harris profile to the B r data between the lobes. Neutral sheet crossing is the B r = 0 location of the fitted function. In addition, start and end times of the crossings period are picked manually. For bifurcated current sheets the crossing will be placed in the centre between the branches.

Auxiliary data used in manual correction: Total |B| and all B field components S/c potential, ion and electron densities should be characteristic of plasma sheet Quality flag numbers: 1: Clear single crossing 2: Stepwise single crossing, e.g. bifurcated curren sheet 3: Several crossings; Harris fitting is used 5: Unclear or uncertain crossing (e.g. on the flank near the magnetopause) 7: Identification uncertain/inaccurate due to insufficient/bad data 9: No boundary determination

Only the outer edge of outer radiation belt is determined For most of the time, Cluster does not cross inner edge. RAPID electron fluxes, 100 keV or several channels. Automated search criterion: time derivative of the flux above a treshold for a certain time.

Only the innermost crossing is recorded. Identification based on s/c potential. We also look for magnetic field rotation or change in variance JSOC predicted location may be used as an initial guess. Auxiliary criteria in manual correction: Ion and electron densities, velocities, spectrograms? In the cusp region there may be no clear crossing. this is denoted by a flag number.

Key parameter: s/c potential, EFW bitmask? Auxiliary parameters: B field, ion and electron density and velocity, spectrograms? Only the innermost crossing is recorded. Only perpendicular shocks can be determined. Parallel shocks are difficult, and a flag number will be given together with an inaccurate sheath to solar wind transition time. If the apogee region is so messy that sheath and solar wind cannot be separated, apogee time is used as reference time.

Contact: Remember, the project only lasts for one year from now and the definition phase will be over in a few months!