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Found 8 entries in the Bibliography.
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2017 
Bayesian Spectral Analysis of Chorus SubElements from the Van Allen Probes We develop a Bayesian spectral analysis technique that calculates the probability distribution functions of a superposition of wavemodes each described by a linear growth rate, a frequency and a chirp rate. The Bayesian framework has a number of advantages, including 1) reducing the parameter space by integrating over the amplitude and phase of the wave, 2) incorporating the data from each channel to determine the model parameters such as frequency which leads to high resolution results in frequency and time, 3) the ability ... Crabtree, Chris; Tejero, Erik; Ganguli, Gurudas; Hospodarsky, George; Kletzing, Craig; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2017 YEAR: 2017 DOI: 10.1002/2016JA023547 
Whistler mode chorus is one of the most important emissions affecting the energization of the radiation belts. Recent laboratory experiments that inject energetic electron beams into a cold plasma have revealed several spectral features in the nonlinear evolution of these instabilities that have also been observed in hightime resolution in situ waveform data. These features include (1) a subelement structure which consists of an amplitude modulation on timescales slower than the bounce time, (2) closely spaced discrete f ... Crabtree, Chris; Ganguli, Gurudas; Tejero, Erik; Published by: Physics of Plasmas Published on: 03/2017 YEAR: 2017 DOI: 10.1063/1.4977539 Dispersion relations; Electron beams; SingingEigenvalues; Van Allen Probes; Whistler waves 
2015 
Nonlinear Generation of Electromagnetic Waves through Induced Scattering by Thermal Plasma We demonstrate the conversion of electrostatic pump waves into electromagnetic waves through nonlinear induced scattering by thermal particles in a laboratory plasma. Electrostatic waves in the whistler branch are launched that propagate near the resonance cone. When the amplitude exceeds a threshold ~5 \texttimes 106 times the background magnetic field, wave power is scattered below the pump frequency with wave normal angles (~59\textdegree), where the scattered wavelength reaches the limits of the plasma column. The scatt ... Tejero, E.; Crabtree, C.; Blackwell, D.; Amatucci, W.; Mithaiwala, M.; Ganguli, G.; Rudakov, L.; Published by: Scientific Reports Published on: 12/2015 YEAR: 2015 DOI: 10.1038/srep17852 
Evolution of lower hybrid turbulence in the ionosphere Threedimensional evolution of the lower hybrid turbulence driven by a spatially localized ion ring beam perpendicular to the ambient magnetic field in space plasmas is analyzed. It is shown that the quasilinear saturation model breaks down when the nonlinear rate of scattering by thermal electron is larger than linear damping rates, which can occur even for low wave amplitudes. The evolution is found to be essentially a threedimensional phenomenon, which cannot be accurately explained by twodimensional simulations. An im ... Ganguli, G.; Crabtree, C.; Mithaiwala, M.; Rudakov, L.; Scales, W.; Published by: Physics of Plasmas Published on: 11/2015 YEAR: 2015 DOI: 10.1063/1.4936281 
Laboratory studies of nonlinear whistler wave processes in the Van Allen radiation belts Important nonlinear wavewave and waveparticle interactions that occur in the Earth\textquoterights Van Allen radiation belts are investigated in a laboratory experiment. Predominantly electrostatic waves in the whistler branch are launched that propagate near the resonance cone with measured wave normal angle greater than 85\textdegree . When the pump amplitude exceeds a threshold \~5\texttimes106 times the background magnetic field, wave power at frequencies below the pump frequency is observed at wave normal angles (\~5 ... Tejero, E.; Crabtree, C.; Blackwell, D.; Amatucci, W.; Mithaiwala, M.; Ganguli, G.; Rudakov, L.; Published by: Physics of Plasmas Published on: 09/2015 YEAR: 2015 DOI: 10.1063/1.4928944 
Laboratory studies of nonlinear whistler wave processes in the Van Allen radiation belts Important nonlinear wavewave and waveparticle interactions that occur in the Earth\textquoterights Van Allen radiation belts are investigated in a laboratory experiment. Predominantly electrostatic waves in the whistler branch are launched that propagate near the resonance cone with measured wave normal angle greater than 85\textordmasculine. When the pump amplitude exceeds a threshold ~5 x10^6 times the back ground magnetic field, wave power at frequencies below the pump frequency is observed at wave normal angles (~55\t ... Tejero, E.; Crabtree, C.; Blackwell, D.; Amatucci, W.; Mithaiwala, M.; Ganguli, G.; Rudakov, L.; Published by: Physics of Plasmas Published on: 08/2015 YEAR: 2015 DOI: 10.1063/1.4928944 Electrostatic Waves; magnetic fields; Nonlinear scattering; Plasma electromagnetic waves; Whistler waves 
2014 
Generation of electromagnetic waves in the very low frequency band by velocity gradient It is shown that a magnetized plasma layer with a velocity gradient in the flow perpendicular to the ambient magnetic field is unstable to waves in the Very Low Frequency band that spans the ion and electron gyrofrequencies. The waves are formally electromagnetic. However, depending on wave vector k⎯⎯=kc/ωpe (normalized by the electron skin depth) and the obliqueness, k⊥/k , where k⊥, are wave vectors perpendicular and parallel to the magnetic field, the waves are closer to electrostatic in nature when k⎯⎯ ... Ganguli, G.; Tejero, E.; Crabtree, C.; Amatucci, W.; Rudakov, L.; Published by: Physics of Plasmas Published on: 01/2014 YEAR: 2014 DOI: 10.1063/1.4862032 
2012 
Weak turbulence in the magnetosphere: Formation of whistler wave cavity by nonlinear scattering We consider the weak turbulence of whistler waves in the in lowβ inner magnetosphere of the earth. Whistler waves, originating in the ionosphere, propagate radially outward and can trigger nonlinear induced scattering by thermal electrons provided the wave energy density is large enough. Nonlinear scattering can substantially change the direction of the wave vector of whistler waves and hence the direction of energy flux with only a small change in the frequency. A portion of whistler waves return to the ionosphere with a ... Crabtree, C.; Rudakov, L.; Ganguli, G.; Mithaiwala, M.; Galinsky, V.; Shevchenko, V.; Published by: Physics of Plasmas Published on: 01/2012 YEAR: 2012 DOI: 10.1063/1.3692092 
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