STATIC SWIA Ram Density Enhancement Test Particle Calculations

STATIC / SWIA Ram Density Enhancement Test Particle Calculations Dave Brain 12 / 09 / 2009

Method • Model of ESA for STATIC / SWIA obtained from Jasper Halekas • 3 D rectangular box placed around model • Test Particles enter model in straight line trajectories from one wall • Particles have incidence angle ( ), random thermal velocity (taken as constant fraction of incident velocity) • Particles travel distances of 1 grid cell per step • Particles bounce of walls in random direction • Particles are traced until they leave the simulation grid, or 20000 steps elapse • Simulation can output trajectories, or # particles visiting each cell

ESA Model

Sample Trajectories v (= -3º)

More Sample Trajectories v (= -3º)

Nominal Case Side View =0, T=0%

Nominal Case Side View =0, T=0%

Nominal Case Flow View =0, T=0%

Nominal Case View in plane of aperture =0, T=0%

Nominal Case Between Hemispheres =0, T=0%

Nominal Case =0, T=0%

= 0° Vary Side View = -1° = -3° = -5° = -7°

= 0° Vary Side View = 1° = 3° = 5° = 7°

Vary - Between Hemispheres = -7° = -5° = -3° = -1° = 0° = 1° = 3° = 5° = 7°

Vary - Aperture Plane = -7° = -5° = -3° = -1° = 0° = 1° = 3° = 5° = 7°

Vary - Residence Time = -7° = -5° = -3° = -1° = 0° = 1° = 3° = 5° = 7°

T = 0% T = 10% Vary T Side View

Vary T - Between Hemispheres T = 1% T = 0% T = 10%

Vary T - Aperture Plane T = 1% T = 0% T = 10%

Vary T - Residence Time T = 1% T = 0% T = 10%

=-7°, T=0% Longer Run 20000 step max 2000000 step max

=-7°, T=0% 20000 step max Longer Run 2000000 step max

New Shape

=-7°, T=0% New Shape

=-7°, T=0% New Shape Old Shape New Shape

=-7°, T=0% Old Shape New Instrument Shape New Shape