Weibel-like Instability Research Articles

Spontaneous generation of magnetic fields in astrophysical dusty plasmas

Two novel mechanisms for spontaneous generation of magnetic fields in dusty plasmas are presented. These are a new dust–plasma battery involving the cross product of the gradient of the dust charge density and the electron–ion pressures, as well as a new Weibel-like instability involving ion pressure anisotropy and resistive electron motions. The relevance of the present investigation to magnetic fields in astrophysical objects is discussed.

Acceleration and scattering of injected electrons in plasma beat wave accelerator experiments*

The results from experiments in which a two-frequency CO2 laser is used to beat-excite large-amplitude, relativistic electron plasma waves in a tunnel-ionized plasma are reported. The plasma wave is diagnosed by injecting a beam of 2 MeV electrons and observing the energy gain and loss of these electrons, as well as the scattering and deflection of the transmitted electrons near 2 MeV. Accelerated electrons up to 30 MeV have been observed. The lifetime of the accelerating structure as seen by small-angle Thomson scattering is about 100 ps, whereas the injected electrons are seen to be scattered or deflected by the plasma for several ns, with diffuse scattering occurring 0.5–1 ns after forming the plasma wave and whole beam deflection occurring at later times. A simple model, which includes laser focusing, ionization, transit time, and relativistic saturation effects, suggests that the wave coherence may be short lived while the wave fields themselves persist for a longer time. This may be the reason for the disparate time scales between the Thomson scattering and the electron scattering diagnostic. The whole beam deflection may be evidence for a Weibel-like instability at later times.

Qualitative Aspects of Underdense Magnetic Fields in Laser-Fusion Plasmas

Computer simulations present evidence that the localized anisotropic heating from resonant absorption drives a Weibel-like instability that generates megagauss magnetic fields for typical laser-fusion parameters. The magnetic fields can inhibit heat transport and partially isotropize the hot electrons.