Today

• Bowshock• Upstream region• Begin Magnetosphere Convection

Use Lorentz Force to explain single particle motions

Note on Biot-Savart Law, see: • http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/biosav.html

What to do first?Treat Earth’s B-field as Barrier in Solar Wind• 1st we have a Bow Shock because Solar

Wind is Supersonic (Super Alfvenic)• New Physics: Upstream Region• Magnetospheath – flow around

magnetopause• Reconnection of BIMF with Earth’s B field

So. Lets talk about the Bow Shock, and work our way into the magnetosphere

Today

From the ACE Spacecraft

http://pixie.spasci.com/DynMod/

How do Shock Waves Work?

• Shock propagation speed: not limited by plasma properties

• Example of sound speed and shock• Example of cars (p. 133 K&R)• Shock Wave causes an irreversible change

of state of the plasma

Upstream

Region Bow Shock

Magnetopause

Whenever you are in the electron foreshock, you see this plasma frequency wave

How to make waves in a plasma?

• EM Mode coupling• Mechanical stimulation• Non-thermal particle distributions =

instability to wave growth• …

Lets talk about Landau Damping and Wave Growth

This is a model of what you see in the foreshock: a background thermal distribution, and a fast ‘beam’ moving up the field line

After the plasma passes through the shock, the state of the plasma has irreversibly changed:

P, T and n (and B) are all changed irreversibly.

We have a new equation of state.

Upstream region

Bow Shock

Now lets examine plasma processes at the magnetopause