Quasistationary magnetic field generated in a plasma by a whistler-mode radio pulse

Aidakina, N. A.; Gushchin, M. E.; Zudin, I. Yu.; Korobkov, S. V.; Костров, А. В.; Стриковский, А. В.

doi:10.1134/s0021364011090025

Cited by 6 publications

(2 citation statements)

References 9 publications

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“…Laboratory setups based on mirror plasma traps are actively used to simulate nonlinear wave-particle interactions in space plasmas [1][2][3][4][5][6][7][8][9][10][11]. In particular, we have reported previously in [12] that a new regime of electron-cyclotron instability has been revealed in a compact axisymmetric mirror trap (the magnetic field in the mirrors is B max = 1.8 T, the distance between the mirrors is 25 cm, the mirror ratio B max /B min = 5) during the plasma decay.…”

Section: Introductionmentioning

confidence: 99%

Interpretation of complex patterns observed in the electron-cyclotron instability of a mirror confined plasma produced by an ECR discharge

Shalashov

Golubev

Gospodchikov

et al. 2012

Plasma Phys. Control. Fusion

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A specific nonlinear regime of electron-cyclotron instability is discussed aimed at explaining the complex temporal patterns of stimulated electromagnetic radiation from a mirror trap with a non-equilibrium plasma typical of an ECR discharge. This regime is characterized by self-modulation of a plasma cyclotron maser due to coherent interference of two counter-propagating unstable waves with degenerate frequencies resulting in the spatial modulation of the amplification coefficient. The proposed simple theoretical model allows one to reproduce the multi-scale time behavior of quasiperiodic pulses of electromagnetic radiation and related precipitation of energetic electrons detected in a laboratory setup based on a magnetic mirror trap with a plasma sustained by mm-wave gyrotron radiation.

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Section: Introductionmentioning

confidence: 99%

Interpretation of complex patterns observed in the electron-cyclotron instability of a mirror confined plasma produced by an ECR discharge

Shalashov

Golubev

Gospodchikov

et al. 2012

Plasma Phys. Control. Fusion

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“…For this reason, the effects of thermal nonlinearity were not developed and f m 1 -the observed cross modulation was most likely due to nonlinearity caused by the averaged ponderomotive force in the spatially inhomogeneous high frequency pump field. It was experimentally shown in [15,16] that the averaged ponderomotive force in the magne tized plasma can result, on one hand, in perturbations of the density and magnetic field owing to the striction effect and, on the other hand, in the generation of closed drift currents perturbing the ambient magnetic field without the modulation of the density. The plasma redistribution rate is limited by the speed of sound, whereas the generation of perturbations of the magnetic field is a fast process.…”

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confidence: 98%

Cross-modulation of whistler waves in a magnetized plasma

et al. 2015

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Waves of the very low and extremely low frequency (VLF and ELF) ranges propagating in the near Earth plasma mainly in the whistler mode are of significant fundamental interest [1], are important for the organi zation and support of very long distance radio commu nication [2], and provide a powerful tool for the diag nostics of the ionosphere and magnetosphere [3]. Wave action on the ionosphere and magnetosphere in the VLF-ELF range is one of the urgent problems of modern plasma geophysics [4]. For the generation of waves with the intensity sufficient for their reliable detection after passage through long ionospheric and magnetospheric paths, ground based stations with powers up to several megawatts are used; the operation of these stations is inevitably accompanied by the development of nonlinear phenomena in the plasma, including the heating and redistribution of the iono spheric plasma [5][6][7], as well as the appearance of fluxes of accelerated charged particles [8,9]. As a result, in the case of the propagation of low frequency waves through common paths, nonlinear effects can result in the mutual enrichment of the frequency spec trum of these waves, in particular, cross modulation, i.e., the modulation of one wave by the law of change of the envelope of another wave [10].Mechanisms of the nonlinear interaction between waves that are responsible for such phenomena are often controversial [11]. Laboratory simulation of nonlinear plasma wave phenomena, as well as theo retical analysis and numerical experiments, is promis ing for the interpretation of data on the interaction of low frequency waves in the near Earth plasma. The advantage of this simulation over a natural experiment is the control of the parameters of the plasma and radi ation, as well as the possibility of multiple reproduc tion of the processes under study with purposeful vari ation of the conditions under which they occur. These experiments can be performed on a limited number of worldwide laboratory facilities which allow the forma tion of a highly uniform column of a low temperature magnetized plasma with dimensions much larger than the wavelength of radiation. The phenomenon of cross modulation of low frequency waves in the mag netized plasma is detected and studied for the first time under laboratory conditions close in similarity parameters to those in the Earth's ionosphere.The experiments were performed on the Krot plasma device in a column of the decaying plasma of an inductive discharge with a length of about 4 m and a diameter of 1.5 m at the electron density n e = 10 10 -10 12 cm -3 , electron temperature T e = 0.5-1 eV, and ambient magnetic field B 0 ~ 100 G (electron cyclotron frequency f ce = 300 MHz). The scaling parameters of the laboratory experiment-plasma density n e and ambient magnetic field strength B 0 -were similar to values in the outer ionosphere and magnetosphere of the Earth with the scaling factor γ = 300-3000 [12]. The collision frequency, which is a nonscaling param eter, is much smaller than the radiation frequ...

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Density irregularities, currents, and magnetic fields generated by pulsed local rf heating of a magnetoplasma: Disturbances in rf antenna vicinity

et al. 2018

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The dynamics of narrow, field-aligned magnetoplasma irregularities is studied, which develop under the action of a short rf pulse. The laboratory experiment is aimed at demonstrating the rapid, so-called “unipolar” plasma transport mode, which is accompanied by excitation of eddy currents, in the case of localized rf heating of plasma electrons. The experimental parameters are chosen in a special way. The size of the heating spot, determined by the diameter of the loop antenna, exceeds the electron gyroradius significantly but is smaller than the ion gyroradius. The rf pulse duration encompasses several electron collision times but is shorter than the gyroperiod of ions. As a result, the electrons, which are strongly magnetized, acquire energy in rf antenna vicinity and can escape the heating region only along the magnetic field B0. In turn, collisionless ions can travel across B0 under the action of space-charge electric fields. For these conditions, redistribution of the plasma occurs with “unipolar” transport coefficients and is accompanied by excitation of electric currents. Weak plasma density disturbances, which are less than 5% of the background, are measured precisely with a microwave resonator probe. Parallel electron currents are obtained from magnetic probe measurements; the ion current across B0 is restored from the density profile modifications in their dynamics. It is shown that the ions traveling across B0 with a velocity about one third of the ion-acoustic velocity can easily close the current loop, which is driven by the parallel motion of heated electrons. This regime of plasma irregularities evolution is discussed in application to previous laboratory measurements, as well as to active ionospheric experiments.

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Quasistationary magnetic field generated in a plasma by a whistler-mode radio pulse

Cited by 6 publications

References 9 publications

Interpretation of complex patterns observed in the electron-cyclotron instability of a mirror confined plasma produced by an ECR discharge

Interpretation of complex patterns observed in the electron-cyclotron instability of a mirror confined plasma produced by an ECR discharge

Cross-modulation of whistler waves in a magnetized plasma

Density irregularities, currents, and magnetic fields generated by pulsed local rf heating of a magnetoplasma: Disturbances in rf antenna vicinity

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