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Review: Frozen in Condition
Plasma and B-field move together
Another way to think of this is by transforming the E field into the moving frame so Ohms Law is
Which just becomes the frozen in condition for large σ
Dominated by vxB term
Evolution of solar magnetic fields over three solar cycles
• http://en.wikipedia.org/wiki/File:Evolution_of_Magnetism_on_the_Sun.ogv
http://www.hao.ucar.edu/research/siv/images/full_pred12.gif
Babcock Theory summary:
1. Differential solar rotation winds up the B-field
2. Flux ropes become buoyant, and pop up (stops B-field growth)
3. Sunspots migrate/diffuse annihilating more equatorward (preceding) spots, and changing polar polarity from with following spots
4. This changes poloidal field and winding adds opposite polarity B (unwinds)
Meridonal flow
Butterfly diagram (sunspots)
Photosphere, Chromosphere, Corona
What is a Plasma?• Nothing less than the 4th state of matter• When a Solid heats up, it melts to
become a liquid• When a Liquid heats up, it evaporates
to become a gas• When a Gas heats up, it ionizes to
become a plasmaNote: Chapter 2 of Kivelson&Russell is an intro to Plasma Physics
Kinetic to potential energy ratio is very large!
particles
Fn=Ae(-1/2mv2/kT)
+qΦ
Shielding of potentials inside a plasma
Debye, or shielding distance in a plasma
Plasma Frequency is given by the square root of the density n, times a constant!