Last time we had an overview of some aspects of the bow shock, magnetosheath, and the magnetosphere.

Now, start with Bow Shock

Today

• Bowshock

• Upstream region (how to make plasma waves)

• 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

• WHAT is an equation of state?

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