Stimulated radio emission of the ionospheric plasma at the second harmonic of the pump wave frequency

1986 ◽  
Vol 29 (1) ◽  
pp. 22-25 ◽  
Author(s):  
A. N. Karashtin ◽  
Yu. S. Korobkov ◽  
V. L. Frolov ◽  
M. Sh. Tsimring
Keyword(s):  
Radio Emission ◽  
Ionospheric Plasma ◽  
Pump Wave ◽  
Second Harmonic ◽  
Wave Frequency ◽  
Pump Wave Frequency

Theory of stimulated scattering of large-amplitude waves

1995 ◽  
Vol 53 (2) ◽  
pp. 213-222 ◽  
Author(s):  
L. Stenflo
Keyword(s):  
Dispersion Relation ◽  
Large Amplitude ◽  
Pump Wave ◽  
Low Frequency ◽  
Wave Frequency ◽  
Nonlinear Coupling ◽  
Stimulated Scattering ◽  
Pump Wave Frequency ◽  
General Dispersion ◽  
Electron Gyrofrequency

By means of the standard fluid equations, we consider the nonlinear coupling between a large-amplitude pump wave and the low-frequency modes in a collisional plasma. We derive the general dispersion relation in order to discuss the case where the pump-wave frequency is not much larger than the electron gyrofrequency.

scholarly journals HF-Induced Modifications of the Electron Density Profile in the Earth’s Ionosphere Using the Pump Frequencies near the Fourth Electron Gyroharmonic

2021 ◽  
Vol 13 (23) ◽  
pp. 4895
Author(s):  
Alexey V. Shindin ◽  
Evgeny N. Sergeev ◽  
Savely M. Grach ◽  
Gennady M. Milikh ◽  
Paul Bernhardt ◽  
...  
Keyword(s):  
Density Profile ◽  
Ionospheric Plasma ◽  
Pump Wave ◽  
Electromagnetic Emission ◽  
Electron Density Profile ◽  
Radio Waves ◽  
F Region ◽  
Plasma Density Profile ◽  
Hybrid Region ◽  
Hf Heating

We discuss results on plasma density profile modifications in the F-region ionosphere that are caused by HF heating with the frequency f0 in the range [(−150 kHz)–(+75 kHz)] around the fourth electron gyroharmonic 4fc. The experiments were conducted at the HAARP facility in June 2014. A multi-frequency Doppler sounder (MDS), which measures the phase and amplitude of reflected sounding radio waves, complemented by the observations of the stimulated electromagnetic emission (SEE) were used for the diagnostics of the plasma perturbations. We detected noticeable plasma expulsion from the reflection region of the pumping wave and from the upper hybrid region, where the expulsion from the latter was strongly suppressed for f0 ≈ 4fc. The plasma expulsion from the upper hybrid region was accompanied by the sounding wave’s anomalous absorption (AA) slower development for f0 ≈ 4fc. Furthermore, slower development and weaker expulsion were detected for the height region between the pump wave reflection and upper hybrid altitudes. The combined MDS and SEE allowed for establishing an interconnection between different manifestations of the HF-induced ionospheric turbulence and determining the altitude of the most effective pump wave energy input to ionospheric plasma by using the dependence on the offset between f0 and 4fc.

scholarly journals Shock location and CME 3D reconstruction of a solar type II radio burst with LOFAR

2018 ◽  
Vol 615 ◽  
pp. A89 ◽  
Author(s):  
P. Zucca ◽  
D. E. Morosan ◽  
A. P. Rouillard ◽  
R. Fallows ◽  
P. T. Gallagher ◽  
...  
Keyword(s):  
Radio Emission ◽  
Radio Burst ◽  
Second Harmonic ◽  
3D Structure ◽  
Large Angle ◽  
Type Ii ◽  
Polytropic Model ◽  
Coronal Shock ◽  
Observational Uncertainty ◽  
Harmonic Source

Context. Type II radio bursts are evidence of shocks in the solar atmosphere and inner heliosphere that emit radio waves ranging from sub-meter to kilometer lengths. These shocks may be associated with coronal mass ejections (CMEs) and reach speeds higher than the local magnetosonic speed. Radio imaging of decameter wavelengths (20–90 MHz) is now possible with the Low Frequency Array (LOFAR), opening a new radio window in which to study coronal shocks that leave the inner solar corona and enter the interplanetary medium and to understand their association with CMEs. Aims. To this end, we study a coronal shock associated with a CME and type II radio burst to determine the locations at which the radio emission is generated, and we investigate the origin of the band-splitting phenomenon. Methods. Thetype II shock source-positions and spectra were obtained using 91 simultaneous tied-array beams of LOFAR, and the CME was observed by the Large Angle and Spectrometric Coronagraph (LASCO) on board the Solar and Heliospheric Observatory (SOHO) and by the COR2A coronagraph of the SECCHI instruments on board the Solar Terrestrial Relation Observatory(STEREO). The 3D structure was inferred using triangulation of the coronographic observations. Coronal magnetic fields were obtained from a 3D magnetohydrodynamics (MHD) polytropic model using the photospheric fields measured by the Heliospheric Imager (HMI) on board the Solar Dynamic Observatory (SDO) as lower boundary. Results. The type II radio source of the coronal shock observed between 50 and 70 MHz was found to be located at the expanding flank of the CME, where the shock geometry is quasi-perpendicular with θBn ~ 70°. The type II radio burst showed first and second harmonic emission; the second harmonic source was cospatial with the first harmonic source to within the observational uncertainty. This suggests that radio wave propagation does not alter the apparent location of the harmonic source. The sources of the two split bands were also found to be cospatial within the observational uncertainty, in agreement with the interpretation that split bands are simultaneous radio emission from upstream and downstream of the shock front. The fast magnetosonic Mach number derived from this interpretation was found to lie in the range 1.3–1.5. The fast magnetosonic Mach numbers derived from modelling the CME and the coronal magnetic field around the type II source were found to lie in the range 1.4–1.6.

scholarly journals Evidence of <i>L</i>-mode electromagnetic wave pumping of ionospheric plasma near geomagnetic zenith

2018 ◽  
Vol 36 (1) ◽  
pp. 243-251 ◽  
Author(s):  
Thomas B. Leyser ◽  
H. Gordon James ◽  
Björn Gustavsson ◽  
Michael T. Rietveld
Keyword(s):  
Electromagnetic Waves ◽  
Ionospheric Plasma ◽  
Pump Wave ◽  
Topside Ionosphere ◽  
Mode Propagation ◽  
Pump Frequency ◽  
Density Peak ◽  
F Region ◽  
Left Handed ◽  
Magnetic Zenith

Abstract. The response of ionospheric plasma to pumping by powerful HF (high frequency) electromagnetic waves transmitted from the ground into the ionosphere is the strongest in the direction of geomagnetic zenith. We present experimental results from transmitting a left-handed circularly polarized HF beam from the EISCAT (European Incoherent SCATter association) Heating facility in magnetic zenith. The CASSIOPE (CAScade, Smallsat and IOnospheric Polar Explorer) spacecraft in the topside ionosphere above the F-region density peak detected transionospheric pump radiation, although the pump frequency was below the maximum ionospheric plasma frequency. The pump wave is deduced to arrive at CASSIOPE through L-mode propagation and associated double (O to Z, Z to O) conversion in pump-induced radio windows. L-mode propagation allows the pump wave to reach higher plasma densities and higher ionospheric altitudes than O-mode propagation so that a pump wave in the L-mode can facilitate excitation of upper hybrid phenomena localized in density depletions in a larger altitude range. L-mode propagation is therefore suggested to be important in explaining the magnetic zenith effect. Keywords. Space plasma physics (active perturbation experiments)

scholarly journals The second harmonic generation in a collisional magnetoactive plasma

2009 ◽  
Vol 7 (1) ◽  
pp. 1-6 ◽  
Author(s):  
B.M. Jovanovic
Keyword(s):  
Second Harmonic Generation ◽  
Nonlinear Equations ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Magnetoactive Plasma ◽  
Frequency Doubling ◽  
Plasma Boundary ◽  
Magnetized Plasma ◽  
Wave Frequency ◽  
System Of Nonlinear Equations

Characteristics for the generation of the second harmonic in homogeneous, collisional and magnetized plasma are investigated theoretically by solving the system of nonlinear equations for the fundamental and second harmonic extraordinary waves. The dependence of the efficiency of the wave frequency doubling on the distance from the plasma boundary and on the collisional frequency has been calculated.

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