Spontaneous Magnetic Fields in Laser-Produced Plasmas

Magnetic Cavitation and the Reemergence of Nonlocal Transport in Laser Plasmas

“…Large magnetic fields -ranging from tens of kilogauss to a megagauss -have been inferred to be important in indirect drive ICF experiments [8,9]. Thus the effect of B-fields on the heat transport in long-pulse laser plasma interactions must be better characterized.…”

“…Whether the heat flow in the plasma is given by Braginskii directly affects the uniformity of the hohlraum conditions which, in turn, can affect the drive uniformity of the capsule and so the fusion yield. The break down of classical heat transport in laser plasmas has been shown to be important in experimental measurements by Hawreliak et al [6] and Gregori et al [7] over nanosecond time-scales.Large magnetic fields -ranging from tens of kilogauss to a megagauss -have been inferred to be important in indirect drive ICF experiments [8,9]. Thus the effect of B-fields on the heat transport in long-pulse laser plasma interactions must be better characterized.…”

MeasuringEandBFields in Laser-Produced Plasmas with Monoenergetic Proton Radiography

“…Previous work has focused largely on regimes in which fields are generated by shortpulse, high-intensity lasers [5,[11][12][13][14], and field measurements were based on Faraday rotation [11,13] and probes [4], or high-order laser harmonics [14]. It has also been proposed that proton radiography could provide a different method for measuring these fields through the deflections they induce in proton trajectories; recent work by Mackinnon et al [15] demonstrated that highresolution images containing deflection information could be obtained, although no direct connections were made between images and fields.…”

“…6(b)] shows a pattern that is significantly more chaotic, containing a B field component with smallscale structure (~20-30% of the bubble size). Several physical mechanisms may contribute to the generation of these small-scale, random structures, in particular those associated with very localized regions of strong ∇n e ×∇T e, including the resonance absorptions at local oblique incidence, filaments, laser hot spots, and instabilities [1][2][3][4][5][6][7]. Use of phase plates [ Fig.…”

“…Many processes can then contribute to field generation and evolution, but their relative importance depends on interaction parameters [1][2][3][4][5][6][7]. For longpulse, low-intensity laser light, the dominant source for B field generation is non-collinear electron density and temperature gradients (∇n e ×∇T e ); the dominant source for E fields is ∇P/n e , a consequence of non-uniform laser irradiation [1][2][3][4][5][6][7]. For circular laser spots, the B fields have a toroidal configuration with scale length comparable to the spot size.…”