Global MHD Simulations of Dayside Magnetopause

Dynamics.

THEMIS Event: May 20, 200820:30 – 22:30

NASA Goddard Space Flight Center

M. M. Kuznetsova, D. G. Sibeck, M. Hesse, L. Rastaetter, T. Gombosi

http://ccmc.gsfc.nasa.gov

BATS-R-US (CSEM, University of Michigan) uses an adaptive grid composed of rectangular blocks arranged in varying degrees of spatial refinement levels.

Resolution at Dayside Magnetopause Including Flanks: 1/16 Re

Global MHD Simulation Model

15 – 20 mln grid cells

N = 2 cm –3 , T = 20,000 Ko , Vx = 300 km/s, |B| = 5 nT

Solar Wind Parameters:

IMF Turning From Northward Orientation (θ = 0) to IMF Clock angle θ < 120o:

Runs with Modeled ConditionsKuznetsova et al, 2004

Cluster BATSRUS

Masha_Kuznetsova_031704_4a

Sub-Solar FTE Structure

Theta = 120o

Pressure

Pressure

Vortices Generation at the FlanksClose to regions of large flow velocity shear

and almost anti-parallel magnetic field.Theta = 120o

Vortices at the Flanks for Southward IMF

Joe_Borovsky_040207_1c

Theta = 180o

THEMIS Dayside Event: May 20, 2008, 20:30 – 22:30

Solar wind propagated from ACE to 33 Re

Global Magnetosphere at 22:00

Resolution at Dayside Magnetopause: 1/16 Re

Weak Magnetic Field Cavity Follows the FTE.

Magnetic field (|B|) Pressure (P)

Density (N) Velocity (|V|)

Time: 20:51:10 UT

- 1 Re

+ 1 Re

- 2 Re

Z = - 1.5 Re Slice

Significant Deviations from 2D Tilted Flux Tube

Start Points for Field Line Tracing at Z = -1.5 Re Slice

.

View from the South

View from the Sun

Start points for field line tracing atZ = - 1.5 Re slice

Component Reconnection Near Sub-Solar Region (Y ~ 0 – 2 Re)And Anti-Parallel Reconnection at Flanks (Y ~ 12 - 15 Re)

FTE at Flanks (Y = 12 Re) is Connected to FTE at the Sub-Solar Region ( Y = 0 ).

Z-slice

Y-slice

X-slice

Slices Through FTE

Y = 0 Z = - 1.5 |Y - 12| < 2

X = 1 |Y – 15| < 2

Magnetic Field Strength

Time: 20:51:10 UT

Slice Through FTE:

Magnetic Field Strength

Y = 0

Time interval: 20:40 – 21:00

FTE Bulge with Strong Core Field

Magnetic field (|B|) Pressure (P)Time: 20:51:10 UT

Density (N) Velocity (|V|)

The plasma pressure exhibit a ring-shaped structure surrounding a central depression

The flow around the flux rope is largest at the magnetosphere side.

Y = 0

+ 2 Re+ 2 Re

Y = 2 ReY = - 2 Re

Signature of Bended Flux Rope (FTE) Near Sub-Solar Region

Bended Flux Rope (FTE) Near Sub-Solar Region

Signature of Bended Flux Rope (FTE)

Signature of Bended Flux Rope

Slice Through FTE:

Magnetic Field Strength

X = 1 |Y - 15| < 2

Time interval: 20:40 – 21:00

Supplementary Slides

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