### Abstract

Language | English |
---|---|

Pages | 052105 |

Journal | Physics of Plasmas |

Volume | 15 |

Issue number | 5 |

DOIs | |

Publication status | Published - May 2008 |

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### Keywords

- ion-acoustic-waves
- packets
- media
- model
- rays

### Cite this

*Physics of Plasmas*,

*15*(5), 052105. https://doi.org/10.1063/1.2913265

}

*Physics of Plasmas*, vol. 15, no. 5, pp. 052105. https://doi.org/10.1063/1.2913265

**Modulational instability of magnetosonic waves in a spin 1/2 quantum plasma.** / Misra, A.P.; Shukla, P.K.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Modulational instability of magnetosonic waves in a spin 1/2 quantum plasma

AU - Misra, A.P.

AU - Shukla, P.K.

PY - 2008/5

Y1 - 2008/5

N2 - The modulational instability (MI) of magnetosonic waves (MSWs) is analyzed, by using a two-fluid quantum magnetohydrodynamic model that includes the effects of the electron-1/2 spin and the plasma resistivity. The envelope modulation is then studied by deriving the corresponding nonlinear Schrodinger equation from the governing equations. The plasma resistivity is shown to play a dissipative role for the onset of MI. In the absence of resistivity, the microscopic spin properties of electrons can also lead to MI. In such a situation, the dominant spin contribution corresponds to a dense quantum plasma with the particle number density, n(0)greater than or similar to 10(28) m(-3). Also, in such a dissipative (absorbing) medium, where the group velocity vector is usually complex for real values of the wave vector, the role of the real group velocity in the propagation of one-dimensional MSW packets in a homogeneous absorbing medium is reported. The effects of quantum spin on the stability/instability conditions of the magnetosonic envelope are obtained and examined numerically. From the nonlinear dispersion relation of the modulated wave packet it is found that the effect of the spin (plasma resistivity) is to decrease (increase) the instability growth rate provided the normalized Zeeman energy does not exceed a critical value. The theoretical results may have relevance to astrophysical (e.g., magnetars) as well as to ultracold laboratory plasmas (e.g., Rydberg plasmas).

AB - The modulational instability (MI) of magnetosonic waves (MSWs) is analyzed, by using a two-fluid quantum magnetohydrodynamic model that includes the effects of the electron-1/2 spin and the plasma resistivity. The envelope modulation is then studied by deriving the corresponding nonlinear Schrodinger equation from the governing equations. The plasma resistivity is shown to play a dissipative role for the onset of MI. In the absence of resistivity, the microscopic spin properties of electrons can also lead to MI. In such a situation, the dominant spin contribution corresponds to a dense quantum plasma with the particle number density, n(0)greater than or similar to 10(28) m(-3). Also, in such a dissipative (absorbing) medium, where the group velocity vector is usually complex for real values of the wave vector, the role of the real group velocity in the propagation of one-dimensional MSW packets in a homogeneous absorbing medium is reported. The effects of quantum spin on the stability/instability conditions of the magnetosonic envelope are obtained and examined numerically. From the nonlinear dispersion relation of the modulated wave packet it is found that the effect of the spin (plasma resistivity) is to decrease (increase) the instability growth rate provided the normalized Zeeman energy does not exceed a critical value. The theoretical results may have relevance to astrophysical (e.g., magnetars) as well as to ultracold laboratory plasmas (e.g., Rydberg plasmas).

KW - ion-acoustic-waves

KW - packets

KW - media

KW - model

KW - rays

UR - http://dx.doi.org/10.1063/1.2913265

U2 - 10.1063/1.2913265

DO - 10.1063/1.2913265

M3 - Article

VL - 15

SP - 052105

JO - Physics of Plasmas

T2 - Physics of Plasmas

JF - Physics of Plasmas

SN - 1070-664X

IS - 5

ER -