Title: Inertial Confinement Fusion
1National Undergraduate Fellowship Program
in Plasma Physics and Fusion Engineering Plasma
Astrophysics Michael Brown Swarthmore
College June 2007 Outline Brief plasma review
(B-fields and MHD) Two important
paradigms Astrophysical objects (solar flares to
galactic jets) Astrophysical processes (dynamos,
reconnection and pulsars)
2Astrophysical Plasma Review
- Magnetic fields
- related to electric fields by Lorentz
transformation - Q why are there large scale B-fields but no
large scale E-fields in the universe? - A ...there are lots of electric monopoles
around to short out electric fields - B-fields are associated with currents but do
currents cause B-fields are vice-versa? - exert forces on currents ForceJxB
- contain energy
3Astrophysical Plasma Review
equations of MHD
Newton II
Ohms Law
Maxwells eqs
induction eq. (curl of Ohm)
4Astrophysical Plasma Review
ramifications of MHD
5Astrophysical Plasma Review
- Frozen-in Flux
- high conductivity Coulomb collisionality drops
with T (so ? T-3/2) - universe is an excellent conductor of electricity
almost everywhere - frozen-in flux
- assume perfectly conducting magnetofluid
- no electric field in a perfect conductor
- if field lines move with respect to fluid then
an electric field is induced - therefore fields move with the fluid!
6Poynting Vector
7Simple 2D Reconnection Theory (Sweet/Parker)
8Reconnection Rate
where Rm is based on the Alfven velocity in the
bulk magnetofluid and on the largest scale of the
system L. Malf is a dimensionless measure of the
reconnection rate or the rate at which magnetic
field lines are annihilated or the direct
electric field. More sophisticated models
Petschek, 1964 and Vasyliunas, 1975 predict a
faster reconnection rate and a smaller ration of
uout/uin. It appears, however that a bound
exists