Frequency upshifting with power intensification of a whistler wave by a collapsing plasma medium

Kalluri, Dikshitulu K.

doi:10.1063/1.361814

Cited by 17 publications

(3 citation statements)

References 14 publications

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“…The concept of USAT variation of the plasma properties (magnetic field) for changing the duration (but not the frequency) of radiation pulses differs from several previously suggested approaches. Both rapid [13,14] and adiabatic [15] change of the plasma density have been proposed and later experimentally realized [16,17] for frequency shifting of radiation. Because plasma ionization results in the transfer of the electromagnetic energy to the kinetic energy of plasma electrons, it results in the reduction of the group velocity and, therefore, cannot be used for pulse compression.…”

mentioning

confidence: 99%

Manipulating Electromagnetic Waves in Magnetized Plasmas: Compression, Frequency Shifting, and Release

Avitzour

Shvets

2008

Phys. Rev. Lett.

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A new approach to manipulating the duration and frequency of microwave pulses using magnetized plasmas is demonstrated. The plasma accomplishes two functions: (i) slowing down and spatially compressing the incident wave, and (ii) modifying the propagation properties (group velocity and frequency) of the wave in the plasma during a uniform in space adiabatic in time variation of the magnitude and/or direction of the magnetic field. The increase in the group velocity results in the shortening of the temporal pulse duration. Depending on the plasma parameters, the frequency of the outgoing compressed pulse can either change or remain unchanged. Such dynamic manipulation of radiation in plasma opens new avenues for manipulating high power microwave pulses.

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mentioning

confidence: 99%

Manipulating Electromagnetic Waves in Magnetized Plasmas: Compression, Frequency Shifting, and Release

Avitzour

Shvets

2008

Phys. Rev. Lett.

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“…If the initial mode is the whistler mode in which the source frequency is less than the cyclotron frequency, ω b , then the frequency of the source wave is increased and the power density is intensified as the plasma collapses [4]. Figure 8 shows the amplitudes of the two modes with respect to T r after the plasma has completely collapsed for ω p0 =10 and ω b =8.4.…”

Section: Wave Conversion By Collapsing Plasmamentioning

confidence: 95%

“…The dielectric constant can be changed from a value less than one to a very high value or vice versa. A magnetoplasma is a suitable electromagnetic medium for frequency shifting [1][2][3][4][5][6][7][8][9][10][11][12][13], since its electromagnetic parameters can be quickly changed. A time-varying magnetoplasma acts like a frequency transformer.…”

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confidence: 99%

Frequency Transformer: Appropriate and Different Models for a Building-up and Collapsing Magnetoplasma Medium

Lade

Lee

Kalluri

2011

J Infrared Milli Terahz Waves

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The interaction of an electromagnetic wave with a time varying medium is governed by the property of conservation of the wavenumber. This property can be utilized to construct a frequency transformer. The time variation in the relative permittivity of the medium is easily produced in a magnetoplasma medium by altering the ionization level. The change of the ionization level can be produced by the dynamic control of the source of ionization. The switching-on action of the source produces a build-up plasma, whereas a switching-off action produces a decaying plasma. Simple mathematical models, however, for the two cases are different. In the case of building-up plasma, the model has to ensure the continuity of the current density and in the case of decaying plasma, the average drift velocity of the surviving electrons has to be continuous. Using these two appropriate models, the effect of the time variation of the plasma frequency as well as the background magnetic field of the magnetoplasma medium are studied. Switching off the external magnetic field for the wave in the magnetoplasma medium converts a whistler wave to a wiggler magnetic field. Similar results are obtained with an intensification of the source wave as well as frequency upshift of the whistler wave for the collapsing plasma medium. By controlling the static magnetic field parameters and the level of ionization, the frequency shift ratio can be changed and the frequency transformer becomes tunable. The principle of frequency up-shifting using plasma permits the generation of signals from easily obtainable frequency bands and upshifts them into frequency bands not easily obtainable by other methods.

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Energetics of electromagnetic wave transformation in a time-varying magnetoplasma medium

Бакунов¹,

Grachev²

2002

Phys. Rev. E

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The transformation of a circularly polarized electromagnetic wave in a magnetoplasma medium with increasing plasma density is considered. The wave propagates along the static magnetic field. Complete analysis, including ion motion, is given both for slow (compared to the wave frequency) and rapid ionization rate. In the case of slow temporal variation of the plasma density, a relation between the energy of the wave and its frequency, which is conserved during the plasma creation process (adiabatic invariant), is found. The existence of significant energy losses follows from the invariant. The dissipative mechanism is explained via consideration of the case of a sudden growth of plasma density in time from one value to another. It is shown that energy transforms into the kinetic energy of carriers, and preionization of the medium plays a principal role in the dissipation process. In the special case of a whistler wave, up to 50% of the energy may be transformed into an ion-cyclotron wave when dense plasma is rapidly created.

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Frequency upshifting with power intensification of a whistler wave by a collapsing plasma medium

Cited by 17 publications

References 14 publications

Manipulating Electromagnetic Waves in Magnetized Plasmas: Compression, Frequency Shifting, and Release

Manipulating Electromagnetic Waves in Magnetized Plasmas: Compression, Frequency Shifting, and Release

Frequency Transformer: Appropriate and Different Models for a Building-up and Collapsing Magnetoplasma Medium

Energetics of electromagnetic wave transformation in a time-varying magnetoplasma medium

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