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Fighting Fluctuations and Collective Modes

Posted: Wed Sep 19, 2007 9:29 pm
by MSimon
Interesting thermal fusion paper

http://www.iop.org/EJ/article/0029-5515 ... a1Ld2wi7Kg

Available for a limited time.

They talk about collective modes and how they interfere with the transfer of particle energy from fusion to the plasma.
Shear Alfv´en wave (SAW) excitations by energetic (E ≈ 1 MeV) ions have been investigated as the primary candidate for causing fluctuation induced transport of fast ions and charged fusion products (from now on referred to as fast or energetic ions) in burning tokamak plasmas. This subject is a clear example of the successful and positive feedback between theory and experiment in the recent years of fusion plasma physics research.

The resonant excitations of SAW modes in toroidal plasmas by fast ions are considered in the present work, revisiting previous analyses that have demonstrated the existence, in general, of two types of modes, i.e. a discrete shear Alfv´en gap mode often called an Alfv´en eigenmode (AE) and an energetic particle continuum mode (EPM) [1]. It can be consistently shown that the resonant fast ion dynamics in toroidal plasmas enters mainly via the magnetic curvature drift coupling in the vorticity equation,
The beauty of Polywell is that we don't have to fight against nature. We can use it.

Wiki on http://en.wikipedia.org/wiki/Alfv%C3%A9n_waves Alfven waves. It is a magnetic phenomenon.

Nice picture of an Alfven wave in a Tokamac:

http://www2.warwick.ac.uk/fac/sci/physi ... /ugsummer/