The linear regime of the two-plasmon decay instability in inhomogeneous plasmas

A linear fluid code solving the equations for the two-plasmon decay (TPD) instability has been developed and used to study the TPD instability. Both absolute and convective modes are observed in the simulations using this code, which show that the absolute modes are located close to the quarter-critical-density surface while the convective modes are located in the lower-density region. The maximum growth rates of the absolute modes measured in the simulations agree well with the theoretical results in the limits of large and small values of the parameter β∝Te2/(Iλ2), where Te is the electron temperature, I is the laser intensity, and λ is the laser wavelength. The simulation results also agree with the β-dependent threshold for absolute TPD. A derivation of the convective gain that retains the dependence on electron temperature and perpendicular mode number is presented and it is in good agreement with the simulation results.

[1]  M. Rosenbluth.  Parametric Instabilities in Inhomogeneous Media , 1972 .

[2]  M. Rosenbluth,et al.  Temporal evolution of a three-wave parametric instability , 1973 .

[3]  M. Rosenbluth,et al.  Parametric decay of electromagnetic waves into two plasmons and its consequences , 1976 .

[4]  Parametric interactions in an inhomogeneous medium of finite extent with abrupt boundaries , 1977 .

[5]  A. Langdon,et al.  Nonlinear saturation and recurrence of the two-plasmon decay instability , 1979 .

[6]  Albert Simon,et al.  On the inhomogeneous two‐plasmon instability , 1983 .

[7]  E. Williams,et al.  A variational approach to parametric instabilities in inhomogeneous plasmas III: Two-plasmon decay , 1997 .

[8]  A. Maximov,et al.  Multibeam effects on fast-electron generation from two-plasmon-decay instability. , 2003, Physical review letters.

[9]  W. Kruer.  Laser plasma interactions with intensities from 1012–1021 W/cm2 , 2003 .

[10]  R. Short,et al.  Theory of three-wave parametric instabilities in inhomogeneous plasmas revisited , 2004 .

[11]  Measurement of preheat due to fast electrons in laser implosions of cryogenic deuterium targets , 2005 .

[12]  L. Perkins,et al.  Shock ignition of thermonuclear fuel with high areal density. , 2006, Physical review letters.

[13]  B. J. MacGowan,et al.  The national ignition facility: path to ignition in the laboratory , 2007 .

[14]  David Strozzi,et al.  Suprathermal electrons generated by the two-plasmon-decay instability in gas-filled Hohlraums , 2008 .

[15]  F. Tsung,et al.  Growth and saturation of convective modes of the two-plasmon decay instability in inertial confinement fusion. , 2009, Physical review letters.

[16]  L. Perkins,et al.  Shock ignition: a new approach to high gain inertial confinement fusion on the national ignition facility. , 2009, Physical review letters.