Control of plasma parameters and electric fields in a microwave‐rf hybrid plasma

1990 ◽  
Vol 67 (10) ◽  
pp. 6114-6117 ◽  
Author(s):  
Hiroharu Fujita ◽  
Yoshihiro Okuno ◽  
Yasunori Ohtsu ◽  
Shinya Yagura
2017 ◽  
Vol 46 (4) ◽  
pp. 299-299
Author(s):  
A. F. Aleksandrov ◽  
A. K. Petrov ◽  
K. V. Vavilin ◽  
E. A. Kral’kina ◽  
P. A. Neklyudova ◽  
...  

2003 ◽  
Vol 10 (1/2) ◽  
pp. 87-92 ◽  
Author(s):  
R. Pottelette ◽  
R. A. Treumann ◽  
M. Berthomier ◽  
J. Jasperse

Abstract. The auroral kilometric radiation (AKR) consists of a large number of fast drifting elementary radiation events that have been interpreted as travelling electron holes resulting from the nonlinear evolution of electron-acoustic waves. The elementary radiation structures sometimes become reflected or trapped in slowly drifting larger structures where the parallel electric fields are located. These latter features have spectral frequency drifts which can be interpreted in terms of the propagation of shock-like disturbances along the auroral field line at velocities near the ion-acoustic speed. The amplitude, speed, and shock width of such localized ion-acoustic shocks are determined here in the fluid approximation from the Sagdeev potential, assuming realistic plasma parameters. It is emphasized that the electrostatic potentials of such nonlinear structures contribute to auroral acceleration.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Schröder ◽  
C. A. Lindstrøm ◽  
S. Bohlen ◽  
G. Boyle ◽  
R. D’Arcy ◽  
...  

AbstractPlasma-wakefield accelerators driven by intense particle beams promise to significantly reduce the size of future high-energy facilities. Such applications require particle beams with a well-controlled energy spectrum, which necessitates detailed tailoring of the plasma wakefield. Precise measurements of the effective wakefield structure are therefore essential for optimising the acceleration process. Here we propose and demonstrate such a measurement technique that enables femtosecond-level (15 fs) sampling of longitudinal electric fields of order gigavolts-per-meter (0.8 GV m−1). This method—based on energy collimation of the incoming bunch—made it possible to investigate the effect of beam and plasma parameters on the beam-loaded longitudinally integrated plasma wakefield, showing good agreement with particle-in-cell simulations. These results open the door to high-quality operation of future plasma accelerators through precise control of the acceleration process.


2020 ◽  
Vol 86 (1) ◽  
Author(s):  
S. Perri ◽  
D. Perrone ◽  
E. Yordanova ◽  
L. Sorriso-Valvo ◽  
W. R. Paterson ◽  
...  

The deviation from thermodynamic equilibrium of the ion velocity distribution functions (VDFs), as measured by the Magnetospheric Multiscale (MMS) mission in the Earth’s turbulent magnetosheath, is quantitatively investigated. Making use of the unprecedented high-resolution MMS ion data, and together with Vlasov–Maxwell simulations, this analysis aims at investigating the relationship between deviation from Maxwellian equilibrium and typical plasma parameters. Correlations of the non-Maxwellian features with plasma quantities such as electric fields, ion temperature, current density and ion vorticity are found to be similar in magnetosheath data and numerical experiments, with a poor correlation between distortions of ion VDFs and current density, evidence that questions the occurrence of VDF departure from Maxwellian at the current density peaks. Moreover, strong correlation has been observed with the magnitude of the electric field in the turbulent magnetosheath, while a certain degree of correlation has been found in the numerical simulations and during a magnetopause crossing by MMS. This work could help shed light on the influence of electrostatic waves on the distortion of the ion VDFs in space turbulent plasmas.


2017 ◽  
Vol 57 (2) ◽  
Author(s):  
Amir Rahimian ◽  
Hossien Zahed

We have conducted particle-in-cell (PIC) simulations of a linearly polarized intensive laser pulse with two different envelopes propagating through a homogeneous fully ionized cold plasma. It is shown that the amplitude of the wake field depends on laser wavelength, pulse duration, electron number density and envelope shape. We have also simulated the effect of applying a longitudinal magnetic field on the wake field excitation process. It is observed that magnetic field enhances the wake field and increases its intensity in all cases. Our results are in agreement with the analytical results presented by Askari and Shahidani [Opt. Laser Technol.45, 613–619 (2013)] and can help choosing the optimum values of affecting laser and plasma parameters in order to reach high accelerating wake electric fields.


2000 ◽  
Vol 64 (3) ◽  
pp. 227-233
Author(s):  
C. RICCARDI ◽  
C. BEVILACQUA ◽  
G. CHIODINI ◽  
E. SINDONI ◽  
M. FONTANESI

This paper concerns experiments on the turbulence of a toroidal magnetoplasma in the presence of a radial electric field. The possibility of reduction of turbulence through the application of an external biasing potential has been evaluated by measuring the electrostatic fluctuations and main plasma parameters.


2020 ◽  
Author(s):  
Remya Bhanu ◽  
David Sibeck ◽  
Mike Ruohoniemi ◽  
Bharat Kunduri ◽  
Alexa Halford ◽  
...  

<p>Electromagnetic ion cyclotron (EMIC) waves are found to be most prevalent during geomagnetic storms and solar wind pressure pulses which provide the necessary free energy for the wave growth. However, they have also been regularly observed
in the absence of these two drivers. These non-storm time and non-pressure pulse EMIC events are very well associated with individual night side injections during substorms. However, not all substorm injections elicit wave activity. Our study aims to determine which substorm trigger wave activity. EMIC events excited during substorm injections are examined and various plasma parameters that are responsible for wave growth are studied. We find that injections that are associated with EMIC waves are also associated with enhanced high latitude ionospheric convection, which are manifestations of strong magnetospheric electric fields. The convective signatures occur at local times similar to those of the observed wave activity.</p>


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