Laboratoire de Physique des Plasmas

On the origin of the quasi-perpendicular

Ion Foreshock: 2D Full-particle simulationPoster session ST1.3 : XY663

(EGU2012-4124)

Philippe Savoini1, Bertrand Lembège2 and Joël Stienlet1

1 LPP/X/UPMC Route de Saclay, 91128 Palaiseau Cédex2 LATMOS/UVSQ/IPSL, Boulevard D’Alembert, 78280 Guyancourt

Experimental data: Evidence of TWO distinct foreshock populations[Paschmann et al., 1981; Gurgiolo et al., 1981; Fuselier et al., 1986, 1995; Eastwood et al., 2005; Kucharek, 2008]

An example of local ion distribution: see poster for more examples

Velocityspace

Field-Aligned Beam (FAB) Gyro-Phase Bunched (GPB)

[Mazelle et al., 2003]

2D PIC Numerical results: Ion foreshock

PitchAngle

No clear separation of FAB and GPB- No ion instabilities- Origin shock front itself- Need refined selection criteria

Two criterion selection : tint and depth

int: Interaction time with the shock wave

Ddepth: Penetration depth into the shock wave

1) Both FAB and GPB recovered

2) FAB: Important interaction time (1 ≤ ci ≤ 5)

➙ Multi-bounces on shock front

3) GPB: Short interaction time( ≤ 1 ci)

➙ Suffer only One bounce ➙ Can be produced by El ➙ No instabilities needed to

produce Non Gyrotropic populations