scholarly journals Effect of a large-amplitude circularly polarized wave on linear beam-plasma electromagnetic instabilities

2003 ◽  
Vol 108 (A12) ◽  
Author(s):  
L. Gomberoff
Keyword(s):  
Large Amplitude ◽  
Circularly Polarized ◽  
Beam Plasma

Parametric instabilities of circularly polarized large-amplitude dispersive Alfvén waves: excitation of parallel-propagating electromagnetic daughter waves

1991 ◽  
Vol 46 (1) ◽  
pp. 107-127 ◽  
Author(s):  
Adolfo F. Viñas ◽  
Melvyn L. Goldstein
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Large Amplitude ◽  
Wave Amplitude ◽  
Pump Wave ◽  
Modulational Instability ◽  
Alfven Wave ◽  
Circularly Polarized ◽  
Background Magnetic Field ◽  
Electromagnetic Instability

We investigate the parametric decay and modulational instabilities of a large-amplitude circularly polarized dispersive Alfvén wave. Our treatment is more general than that of previous derivations based on the two-fluid equations in that we allow for propagation of the unstable daughter waves at arbitrary angles to the background magnetic field, although our main concern in this paper is the exploration of new aspects of propagation parallel to the DC magnetic field. In addition to the well-known coupling of pump waves to electrostatic daughter waves, we find a new parametric channel where the pump wave couples directly to electromagnetic daughter waves. Excitation of the electromagnetic instability occurs only for modulation (k/k0 ≤ 1) and not for decay (k/k0 < 1). In contrast with the modulational instability excited by the electrostatic coupling, the electromagnetic modulational instability exists for both left-hand (K > 0) and right-hand (K < 0) polarization. For large k/k0, the electromagnetic channel dominates, while at lower values the electrostatic channel has a larger growth rate for modest values of dispersion, pump-wave amplitude and plasma β. Unlike the electrostatic modulational instability, the growth rate of the electromagnetic instability increases monotonically with increasing pump wave amplitude. This analysis confirms that, for decay, the dominant process is coupling to electrostatic daughter waves, at least for parallel propagation. For modulation, the coupling to electromagnetic daughter waves usually dominates, suggesting that the parametric modulational instability is really an electromagnetic phenomenon.

Large-amplitude circularly polarized electromagnetic waves in magnetized plasma

2014 ◽  
Vol 21 (5) ◽  
pp. 054501 ◽  
Author(s):  
I. Y. Vasko ◽  
A. V. Artemyev ◽  
L. M. Zelenyi
Keyword(s):  
Large Amplitude ◽  
Electromagnetic Waves ◽  
Magnetized Plasma ◽  
Circularly Polarized

On the stability of self-consistent large-amplitude waves in a cold plasma. Part 3. Transverse circularly polarized waves in the presence of a large-scale magnetic field

1979 ◽  
Vol 21 (1) ◽  
pp. 43-50 ◽  
Author(s):  
M. A. Lee ◽  
I. Lerche
Keyword(s):  
Magnetic Field ◽  
Large Amplitude ◽  
Cold Plasma ◽  
Large Scale ◽  
Circularly Polarized ◽  
Polarized Waves ◽  
Large Scale Magnetic Field ◽  
Self Consistent ◽  
Instability Rate ◽  
The Stability

We demonstrate that a self-consistent large-amplitude circularly polarized wave, propagating in a cold plasma in the presence of a large-scale magnetic field, is unstable if the constant bulk streaming speed of the plasma is zero in the frame in which the wave depends oniy on time. The growth rate is of the order of the plasma frequency or the gyrofrequency at short perturbation wavelengths, and is proportional to the perturbation wave vector at long wavelengths. For nonzero but small streaming the instability rate increases for one streaming direction and decreases for the other. We conclude that instability is the rule rather than the exception for large-amplitude waves in a cold plasma.

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