Doppler-Shifted Cyclotron Resonance and Alfvén Wave Damping in Bismuth

1962 ◽  
Vol 9 (10) ◽  
pp. 421-423 ◽  
Author(s):  
Jordan Kirsch ◽  
P. B. Miller
Keyword(s):  
Cyclotron Resonance ◽  
Alfven Wave ◽  
Wave Damping

scholarly journals ECR plasma source for heavy ion beam charge neutralization

2003 ◽  
Vol 21 (1) ◽  
pp. 37-40 ◽  
Author(s):  
PHILIP C. EFTHIMION ◽  
ERIK GILSON ◽  
LARRY GRISHAM ◽  
PAVEL KOLCHIN ◽  
RONALD C. DAVIDSON ◽  
...  
Keyword(s):  
Cyclotron Resonance ◽  
Electron Cyclotron Resonance ◽  
Ion Beam ◽  
Low Pressure ◽  
Heavy Ion ◽  
Electron Cyclotron ◽  
Wave Damping ◽  
Charge Neutralization ◽  
Ecr Plasma ◽  
Ecr Source

Highly ionized plasmas are being considered as a medium for charge neutralizing heavy ion beams in order to focus beyond the space-charge limit. Calculations suggest that plasma at a density of 1–100 times the ion beam density and at a length ∼0.1–2 m would be suitable for achieving a high level of charge neutralization. An Electron Cyclotron Resonance (ECR) source has been built at the Princeton Plasma Physics Laboratory (PPPL) to support a joint Neutralized Transport Experiment (NTX) at the Lawrence Berkeley National Laboratory (LBNL) to study ion beam neutralization with plasma. The ECR source operates at 13.6 MHz and with solenoid magnetic fields of 1–10 gauss. The goal is to operate the source at pressures ∼10−6 Torr at full ionization. The initial operation of the source has been at pressures of 10−4–10−1 Torr. Electron densities in the range of 108 to 1011 cm−3 have been achieved. Low-pressure operation is important to reduce ion beam ionization. A cusp magnetic field has been installed to improve radial confinement and reduce the field strength on the beam axis. In addition, axial confinement is believed to be important to achieve lower-pressure operation. To further improve breakdown at low pressure, a weak electron source will be placed near the end of the ECR source. This article also describes the wave damping mechanisms. At moderate pressures (> 1 mTorr), the wave damping is collisional, and at low pressures (< 1 mTorr) there is a distinct electron cyclotron resonance.

scholarly journals Phase mixing of Alfvén waves in two-dimensional magnetic plasma configurations with exponentially decreasing density

2018 ◽  
Vol 620 ◽  
pp. A44
Author(s):  
Michael S. Ruderman ◽  
Nikolai S. Petrukhin
Keyword(s):  
Magnetic Field ◽  
Shear Viscosity ◽  
Alfven Waves ◽  
Mhd Equations ◽  
Alfven Wave ◽  
Alfvén Waves ◽  
Field Variation ◽  
Characteristic Scale ◽  
Wave Damping ◽  
Magnetic Plasma

We study damping of phase-mixed Alfvén waves propagating in axisymmetric magnetic plasma configurations. We use the linear magnetohydrodynamic (MHD) equations in the cold plasma approximation. The only dissipative process that we take into account is shear viscosity. We reduce the MHD equations describing the Alfvén wave damping to a Klein–Gordon-type equation. We assume that the two terms in this equation, one describing the effect of inhomogeneity and the other the effect of viscosity, are small. Then we use the WKB method to derive the expression describing the wave energy flux attenuation with the height. We apply the general theory to particular equilibria with the exponentially divergent magnetic field lines with the characteristic scale H. The plasma density exponentially decreases with the height with the characteristic scale Hρ. We study the wave damping for typical parameters of coronal plumes and various values of the wave period, the characteristic scale of the magnetic field variation H, and kinematic shear viscosity ν. We show that to have an appreciable wave damping at the height 6H we need to increase shear viscosity by at least six orders of magnitude in comparison with the value given by the classical plasma theory. Another important result is that the efficiency of wave damping strongly depends on the ratio H/Hρ. It increases fast when H/Hρ decreases. We present a physical explanation of this phenomenon.

scholarly journals CORONAL HEATING BY SURFACE ALFVÉN WAVE DAMPING: IMPLEMENTATION IN A GLOBAL MAGNETOHYDRODYNAMICS MODEL OF THE SOLAR WIND

2012 ◽  
Vol 756 (2) ◽  
pp. 155 ◽  
Author(s):  
R. M. Evans ◽  
M. Opher ◽  
R. Oran ◽  
B. van der Holst ◽  
I. V. Sokolov ◽  
...  
Keyword(s):  
Solar Wind ◽  
Coronal Heating ◽  
Alfven Wave ◽  
Wave Damping

scholarly journals Solar off-limb line widths with SUMER: revised value of the non-thermal velocity and new results

2009 ◽  
Vol 27 (9) ◽  
pp. 3551-3558 ◽  
Author(s):  
L. Dolla ◽  
J. Solomon
Keyword(s):  
Solar Wind ◽  
Cyclotron Resonance ◽  
Alfven Waves ◽  
Stray Light ◽  
Alfven Wave ◽  
Alfvén Waves ◽  
Thermal Velocity ◽  
Line Profiles ◽  
Lower Corona ◽  
Ion Cyclotron

Abstract. Alfvén waves and ion-cyclotron absorption of high-frequency waves are frequently brought into models devoted to coronal heating and fast solar-wind acceleration. Signatures of ion-cyclotron resonance have already been observed in situ in the solar wind and in the upper corona. In the lower corona, one can use the line profiles to infer the ion temperatures. But the value of the so-called "non-thermal" (or "unresolved") velocity, potentially related to the amplitude of Alfvén waves propagating in the corona, is critical in firmly identifying ion-cyclotron preferential heating. In a previous paper, we proposed a method to constrain both the Alfvén wave amplitude and the preferential heating, above a polar coronal hole observed with the SUMER/SOHO spectrometer. Taking into account the effect of instrumental stray light before analysing the line profiles, we ruled out any direct evidence of damping of the Alfvén waves and showed that ions with the lowest charge-to-mass ratios were preferentially heated. We re-analyse these data here to correct the derived non-thermal velocity, and we discuss the consequences on the main results. We also include a measure of the Fe VIII 1442.56 Å line width (second order), thus extending the charge-to-mass ratio domain towards ions more likely to experience cyclotron resonance.

scholarly journals Compressional Alfvén Wave Propagation Below Ion Cyclotron Frequency

1968 ◽  
Vol 21 (2) ◽  
pp. 129 ◽  
Author(s):  
RC Cross ◽  
JA Lehane
Keyword(s):  
Wave Propagation ◽  
Cyclotron Resonance ◽  
Cyclotron Frequency ◽  
Cutoff Frequency ◽  
Compressional Wave ◽  
Alfven Wave ◽  
Alfvén Waves ◽  
Ion Cyclotron Resonance ◽  
Wave Measurements ◽  
Ion Cyclotron

When the compressional wave cutoff frequency is below ion cyclotron frequency both compressional and torsional Alfven waves may be present simultaneously. Oompressional wave measurements in this regime are particularly important because of their relevance to certain ion cyclotron resonance heating experiments. This paper extends the work of others in this important regime.

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