Nonlinear oscillatory waveguide propagation in a plasma

Sodha, M. S.; Prasad, S.; Tripathi, V. K.

doi:10.1007/bf00883558

Cited by 11 publications

(3 citation statements)

References 5 publications

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“…Following Akhmanov et al [1], A(x, z, t) can be expressed as A(x, z, t) = A 0 (x, z, t)e −ikz , A 0 (x, z, t) = A 00 (x, z, t)e −iks(x,z,t) , where k = ω c ε 1/2 0 , and A 0 and s are real. Following Sodha et al [2] [cf. (35) and (36), p. 640], the solution in the paraxial ray approximation can be written as…”

Section: Self-distortion Of the Electromagnetic Wavementioning

confidence: 99%

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Distortion of an amplitude modulated electromagnetic signal with time-dependent dust charging

Gahlot

Walia²,

Sharma³

et al. 2011

J. Plasma Phys.

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A large amplitude modulated Gaussian electromagnetic beam propagating in a dusty plasma with dust charge fluctuations has been studied. The electrons are heated non-uniformly by the electromagnetic beam. For non-steady state, we obtain nonlinear current density in the presence of dust grains. This expression has been used to study the non-stationary self-focusing and resulting self-distortion of the amplitude modulated electromagnetic beam. It has been observed that the dust charge fluctuation increases the self-focusing of electromagnetic beam. It is also found that the effect of dust charge fluctuations is significant on the modulation index.

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Section: Self-distortion Of the Electromagnetic Wavementioning

confidence: 99%

“…Transient and time-periodic self-focusing of a laser beam has been a fascinating field of research for many-many years [1][2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Distortion of an amplitude modulated electromagnetic signal with time-dependent dust charging

Gahlot

Walia²,

Sharma³

et al. 2011

J. Plasma Phys.

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“…The steady state and transient self-focusing of Gaussian e .m. waves in collisional and collisionless plasmas have also been studied theoretically [4][5][6][7] . The plasmas are however assumed to be time-independent .…”

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confidence: 99%

Transient Self-focusing of Electromagnetic Waves in a Weakly Ionized Decaying Plasma

1976

Optica Acta: International Journal of Optics

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Using a phenomenological approach for the evaluation of nonlinear current density and the W .K .B . and paraxial ray approximations for solving the wave equation, the transient self-focusing of a Gaussian electromagnetic beam in a decaying weakly ionized collisional plasma has been investigated . The non-linearity arises due to the heating and redistribution of carriers in the plasma . When the decay time for the electron density (Td) and non-linearity relaxation time (T E) are comparable, the self-focusing of a portion of the wave depends on the intensity of the preceding portion of the wave . For a plasma having Td larger than T E, the quasi-steady-state analysis is applicable . Further, our results for the reduction in spot size due to nonlinearity are in reasonable agreement with the experimental results of Eremin, Litvak and Poluyakhtov . IntroductionThe plasmas with time-varying electron density are encountered in laserplasma interactions, discharge tubes, ionosphere and many other laboratory experiments . The studies of such plasmas have become important owing to their applications in communications . The earlier studies [1-3] on propagation of electromagnetic waves in such plasmas are restricted mainly to the quasisteady-state conditions and linear regime . The non-linear interaction of uniform plane electromagnetic waves with time-dependent plasmas has been investigated by Papa [2] . The results are applicable to the quasi-steady-state case when the decay time of the plasma (T d) is larger than the energy relaxation time (-r f) of the electrons . Recently the non-linear propagation of non-uniform electromagnetic waves (Gaussian in space) in a plasma has become very important . The steady state and transient self-focusing of Gaussian e .m. waves in collisional and collisionless plasmas have also been studied theoretically [4][5][6][7] . The plasmas are however assumed to be time-independent . The experimental results on self-focusing of e .m. waves in plasmas are rarely available . In the case where the experimental results are available, the inherent non-uniformity and non-stationary nature of the plasma make the interpretation of the results complicated .In the present paper we have investigated the problem of quasi-steady state and transient self-focusing of a Gaussian electromagnetic beam in a decaying weakly ionized collisional plasma . The treatment is also relevant to the experiment available on thermal self-focusing of microwaves in a decaying discharge

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Two Methods of Space-Time Energy Densification

Sahlin

1976

Energy Storage, Compression, and Switching

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With a viev to the goal of net energy production from a DT microexplosion, we study two ideas (methods) through which (separately or in combination) energy may be "concentrated" into a small volume and short period of time-the so-called space-time energy densification or compression. We first discuss the advantages and disadvantages of lasers and relativistic electron-beam {E-beam) machines as the sources of such energy and identify the amplification of laser pulses as a key factor in energy compression. The pulse length of present relativistic E-beam machines is the most serious linitatioo of this pulsed-power source. The first energy-compression idea we discuss is the reasonably efficient production of short-duration, hi^h-current relativistic electron pulses by the self interruption and restrii;e of a current in a plasna pinch due to the rapid onset uf strong turbulence. A 1-MJ plasma focus based on this method is nearing completion at this Laboratory. The second energy-compression Idea is based on laserpulse producti , through the parametric amplification of a self-similar or solitary wave pulse, for which analogs can be found in other wave processes. Specifically, the second energy-compression idea is a proposal for parametric amplification of a solitary, transverse magnetic pulse in a coaxial cavity with a Bennett dielectric rod as an inner coax. Amplifiers of this type can be driven by the pulsed power frorr a relativistic K-beam machine. If the end of the inner dielectric coax is nade of LiDT or another fusionable material, the amplified pulse can directly drive a fusion reaction-there would be no need to switch the pulse out of the system toward a remote target.

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Nonlinear oscillatory waveguide propagation in a plasma

Cited by 11 publications

References 5 publications

Distortion of an amplitude modulated electromagnetic signal with time-dependent dust charging

Distortion of an amplitude modulated electromagnetic signal with time-dependent dust charging

Transient Self-focusing of Electromagnetic Waves in a Weakly Ionized Decaying Plasma

Two Methods of Space-Time Energy Densification

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