On the behavior of ultraintense laser produced hot electrons in self-excited fields

Copyright 2007 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Plasmas, 14(4), 040706, 2007 and may be found at http://dx.doi.org/10.1063/1.272230

Characterization of preplasma produced by an ultrahigh intensity laser system

Copyright 2004 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Plasmas, 11(8), 3721-3725, 2004 and may be found at http://dx.doi.org/10.1063/1.176077

Focus optimization of relativistic self-focusing for anomalous laser penetration into overdense plasmas (super-penetration)

"Relativistic electron motion in a plasma due to an intense laser pulse modifies the refractive index and leads to two effects: relativistic induced transparency and relativistic self-focusing. A combination of the above two effects enables transmission of laser energy deep into plasmas which is useful for fast ignition of inertial fusion. This so-called super-penetration sensitively depends on the focal position of the laser intensity due to the inhomogeneous density profile of the plasma and convergence of the laser pulse by final focusing optics. Experiments were conducted at vacuum focused laser intensities between 3.3 and 4. 4 x 1018 W cm[?]2 at peak plasma densities between 23 and 75nc, where nc is the critical density of the plasma. We introduced a scenario: the laser beam diameter at nc/4 density must be smaller than the plasma wavelength to achieve whole beam self-focusing. An optimum focus was found experimentally by measuring the plasma channel, laser transmittance and electron spectra. All three data are consistent with one another and numerical calculations based on a paraxial approximation model suggest that this optimum focus corresponds to the scenario described above."http://deepblue.lib.umich.edu/bitstream/2027.42/64206/1/ppcf8_10_105011.pd

Relativistic laser channeling in plasmas for fast ignition

We report an experimental observation suggesting plasma channel formation by focusing a relativistic laser pulse into a long-scale-length preformed plasma. The channel direction coincides with the laser axis. Laser light transmittance measurement indicates laser channeling into the high-density plasma with relativistic self-focusing. A three-dimensional particle-in-cell simulation reproduces the plasma channel and reveals that the collimated hot-electron beam is generated along the laser axis in the laser channeling. These findings hold the promising possibility of fast heating a dense fuel plasma with a relativistic laser pulse

Study of ultraintense laser propagation in overdense plasmas for fast ignition

Copyright 2009 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Plasmas, 16(5), 056307, 2009 and may be found at http://dx.doi.org/10.1063/1.310191

Hot electron emission limited by self-excited fields from targets irradiated by ultra-intense laser pulses

"A large number of hot electrons exceeding the Alfven current can be produced when an ultra-intense laser pulse irradiates a solid target. Self-excited electrostatic and magnetic fields at the target rear could influence the hot electron transport. To investigate the influence, we measure the hot electrons when a pre-plasma is created on the target rear surface and verify an increase of the electron number by a factor of 2 comparing to the no rear plasma case. The increase may be caused because of changes in the electrostatic potential formation process. The retardation of the potential formation is shown using a particle-in-cell simulation. The electron number escaping within the retardation time duration is consistent with our estimation taking the Alfven current into account."http://deepblue.lib.umich.edu/bitstream/2027.42/64170/1/jpconf8_112_022093.pd