The Magnetosphere Feifei Jiang UCLA fjiangigpp ucla edu

The Magnetosphere Feifei Jiang, UCLA fjiang@igpp. ucla. edu

Outline • Magnetic field • Plasmas • Currents • Force Balance

The Earth’s Main Field Dipole in spherical coordinates L L 0 Dipole field lines

The Stretched Tail Magnetic Reconnection Viscous Interaction

The Tail Plasma Sheet Plasma parameters in the central plasma sheet E B EXB N = 0. 1~0. 5 cm-3 Ti = 2~10 ke. V Ti/Te = 6 Mantle particles will Ex. B drift towards the center of the tail To move from the center of mantle to the center of plasma sheet

The Radiation Belts One proton belt: • 0. 1~ 100 Me. V, peak near L~1. 8 Two electron belts with a slot region: • For E> 1 Me. V peak near L=1. 6 and 4. 0 Re Source: ~ke. V particles in the plasma sheet How are these particles energized? 1. Acceleration by chorus waves 2. Radial diffusion 3. Substorm injection

The Plasmasphere Cold, dense plasmas: Guiding center drift velocity • ~103 cm-3, ~1 e. V • Plasmapause, 3~5 Re depending on geomagnetic activity • 2 sources: Polar wind and convection Stagnation Point

Currents in the Magnetosphere

Magnetopause Current The current crossing y=y 0 per unit length in z

Tail Current

Field-aligned current Region 1 current: Flow shear/parallel flow vorticity Region 2 current: surfaces of constant pressure are not aligned with magnetic shells

Ring Current Magnetic field of a current loop Dessler-Parker-Sckopke relationship

Force Balance At the magnetopause nose K=0. 89, a ~ 2. 4 At the magnetopause on the tail side At the tail plasma sheet

Thank you

Particle Motion in the Magnetosphere