Narrow cyclotron harmonic absorption resonances of stimulated electromagnetic emission in the ionosphere

Tb, Leyser; Thidé, Bo; Goodman, S.; Waldenvik, M.; Veszelei, E.; Грач, С. М.; An, Karashtin; Gp, Komrakov; Ds, Kotik

doi:10.1103/physrevlett.68.3299

Cited by 46 publications

(23 citation statements)

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“…This is due to the wide range of ionospheric diagnostic information that has become available from the SEE spectrum. It can be used to determine the local magnetic field magnitude [Leyser et al, 1992], to determine the conditions for acceleration of electrons [Leyser et al, 2001], and to measure electron temperatures [Bernhardt et al, 2009] and ion composition [Bernhardt et al, 2010]. Parametric decay of the high-frequency pump wave, transmitted from the ground into other plasma wave modes, is considered to be the underlying theory for generation of the features in the SEE spectrum [Leyser et al, 2001].…”

Section: Introductionmentioning

confidence: 99%

First observations of minority ion (H⁺) structuring in stimulated radiation during second electron gyroharmonic heating experiments

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Samimi

et al. 2013

Geophysical Research Letters

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[1] This work presents the first observations of unique narrowband emissions ordered near the hydrogen ion (H + ) gyrofrequency (f cH ) in the stimulated electromagnetic emission spectrum when the transmitter is tuned near the second electron gyroharmonic frequency (2f ce ) during ionospheric modification experiments. The frequency structuring of these newly discovered emission lines is quite unexpected since H + is known to be a minor constituent in the interaction region which is near 160 km altitude. The spectral lines are typically shifted from the pump wave frequency by harmonics of a frequency about 10% less than f cH ( 800 Hz) and have a bandwidth of less than 50 Hz which is near the O + gyrofrequency f cO . A theory is proposed to explain these emissions in terms of a parametric decay instability in a multi-ion species plasma due to possible proton precipitation associated with the disturbed conditions during the heating experiment. The observations can be explained by including several percent H + ions into the background plasma.

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Section: Introductionmentioning

confidence: 99%

First observations of minority ion (H⁺) structuring in stimulated radiation during second electron gyroharmonic heating experiments

Bordikar

Scales

Samimi

et al. 2013

Geophysical Research Letters

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“…The pump frequency f 0 was chosen to be near sf g , where s 4 (May, 1993) or s 6 (September, 1991). The relation between f 0 and sf g was determined from an analysis of SEE spectra [1,2], which provide very accurate diagnostics of this relationship [3][4][5][6]. To obtain data at different f 0 2 sf g we changed f 0 in steps of 5-15 kHz during pump "off" periods.…”

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Multifrequency Doppler Radar Observations of Electron Gyroharmonic Effects during Electromagnetic Pumping of the Ionosphere

et al. 1997

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Experimental results of multifrequency HF Doppler radar studies during electromagnetic pumping of the ionosphere from the ground are reported. The Doppler shifts of the radar waves after turn-on of the vertically injected HF pump wave depend on the pump frequency and exhibit, at relatively large reflection altitudes, opposite signs for pump frequencies above or below an electron gyroharmonic. The results are interpreted in terms of pump-induced plasma expulsion and enhanced ionization. For pump frequencies at a gyroharmonic, a minimum of plasma perturbation is detected with the radars. [S0031-9007(96)02265-X] PACS numbers: 94.20.Bb, 52.25.Sw, 52.35.Mw, 94.20.Tt

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“…Various SEE spectral features can be studied as diagnostic tools that give information about the condition of the ionosphere and nonlinear plasma processes (Leyser, 2001). For instance, electron temperature (Bernhardt et al, 2009) or amplitude of the local geomagnetic field (Leyser, 1992) in the interaction region may be estimated. Parametric decay of the pump field into new plasma waves has been introduced as a fundamental process that generates SEE.…”

Section: Introductionmentioning

confidence: 99%

On ion gyro-harmonic structuring in the stimulated electromagnetic emission spectrum during second electron gyro-harmonic heating

et al. 2012

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Abstract. Recent observations show that, during ionospheric heating experiments at frequencies near the second electron gyro-harmonic, discrete spectral lines separated by harmonics of the ion-gyro frequency appear in the stimulated electromagnetic emission (SEE) spectrum within 1 kHz of the pump frequency. In addition to the ion gyro-harmonic structures, on occasion, a broadband downshifted emission is observed simultaneously with these spectral lines. Parametric decay of the pump field into upper hybrid/electron Bernstein (UH/EB) and low-frequency ion Bernstein (IB) and oblique ion acoustic (IA) modes is considered responsible for generation of these spectral features. Guided by predictions of an analytical model, a two-dimensional particle-in-cell (PIC) computational model is employed to study the nonlinear processes during such heating experiments. The critical parameters that affect the spectrum, such as whether discrete gyroharmonic on broadband structures is observed, include angle of the pump field relative to the background magnetic field, pump field strength, and proximity of the pump frequency to the gyro-harmonic. Significant electron heating along the magnetic field is observed in the parameter regimes considered.

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Narrow cyclotron harmonic absorption resonances of stimulated electromagnetic emission in the ionosphere

Cited by 46 publications

References 10 publications

First observations of minority ion (H⁺) structuring in stimulated radiation during second electron gyroharmonic heating experiments

First observations of minority ion (H⁺) structuring in stimulated radiation during second electron gyroharmonic heating experiments

Multifrequency Doppler Radar Observations of Electron Gyroharmonic Effects during Electromagnetic Pumping of the Ionosphere

On ion gyro-harmonic structuring in the stimulated electromagnetic emission spectrum during second electron gyro-harmonic heating

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Narrow cyclotron harmonic absorption resonances of stimulated electromagnetic emission in the ionosphere

Cited by 46 publications

References 10 publications

First observations of minority ion (H+) structuring in stimulated radiation during second electron gyroharmonic heating experiments

First observations of minority ion (H+) structuring in stimulated radiation during second electron gyroharmonic heating experiments

Multifrequency Doppler Radar Observations of Electron Gyroharmonic Effects during Electromagnetic Pumping of the Ionosphere

On ion gyro-harmonic structuring in the stimulated electromagnetic emission spectrum during second electron gyro-harmonic heating

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First observations of minority ion (H⁺) structuring in stimulated radiation during second electron gyroharmonic heating experiments

First observations of minority ion (H⁺) structuring in stimulated radiation during second electron gyroharmonic heating experiments