Heat Transport in Spatially Fluctuating Laser-Generated D.C. Magnetic Fields
In this paper, we investigate anomalous electron thermal conduction perpendicular to d.c. laser-generated B fields. We find that d.c. spatial fluctuations δB about a mean field BO can produce large enhancements in the cross-field diffusion coefficient, over its δB = 0 value. There are by now a multitude of suggested sources for laser-generated d.c. magnetic fields. When all these processes act at once, the likely result is an overall “average” field BO which is probably toroidal, due to Vn x VT sources, plus a spatially fluctuating component δB due to the sum of all the other field sources. For parameters appropriate to laser fusion experiments, we use a quasilinear model to describe the effect of particle scattering by fluctuations δB. We find that if δB ⪝ BO, the diffusion coefficient can be comparable to the Bohm value: D ∼ (v t 2 /Ωc(∣δB∣)2/B o 2 ). Next we discuss the effect of field-line wandering on the flux. Finally, we investigate an analogue of neoclassical diffusion appropriate to laser-plasma conditions.
KeywordsHeat Transport Resonant Scattering Vacuum Wavelength Collisionless Regime Bounce Motion
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