Saturation of multi-laser beams laser-plasma instabilities from stochastic ion heating
- Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)
- Theoretical Physics Institute, University of Alberta, Edmonton, Alberta T6G2G7 (Canada)
Cross-beam energy transfer (CBET) has been used as a tool on the National Ignition Facility (NIF) since the first energetics experiments in 2009 to control the energy deposition in ignition hohlraums and tune the implosion symmetry. As large amounts of power are transferred between laser beams at the entrance holes of NIF hohlraums, the presence of many overlapping beat waves can lead to stochastic ion heating in the regions where laser beams overlap [P. Michel et al., Phys. Rev. Lett. 109, 195004 (2012)]. This increases the ion acoustic velocity and modifies the ion acoustic waves’ dispersion relation, thus reducing the plasma response to the beat waves and the efficiency of CBET. This pushes the plasma oscillations driven by CBET in a regime where the phase velocities are much smaller than both the electron and ion thermal velocities. CBET gains are derived for this new regime and generalized to the case of multi ion species plasmas.
- OSTI ID:
- 22228097
- Journal Information:
- Physics of Plasmas, Vol. 20, Issue 5; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BEAM-PLASMA SYSTEMS
DISPERSION RELATIONS
ELECTRONS
ENERGY ABSORPTION
ENERGY LOSSES
ENERGY TRANSFER
GAIN
ION ACOUSTIC WAVES
IONS
LASER IMPLOSIONS
LASER-PRODUCED PLASMA
NEODYMIUM LASERS
PHASE VELOCITY
PLASMA HEATING
PLASMA INSTABILITY
STOCHASTIC PROCESSES
THERMODYNAMICS
THERMONUCLEAR IGNITION
US NATIONAL IGNITION FACILITY