scholarly journals Reflection at the resonance layer of the fast Alfvén wave in ion cyclotron heating

1990 ◽  
Vol 2 (9) ◽  
pp. 2185-2190 ◽  
Author(s):  
C. Chow ◽  
V. Fuchs ◽  
A. Bers
Keyword(s):  
Alfven Wave ◽  
Ion Cyclotron

Alfvén wave heating of a cylindrical plasma using axisymmetric waves. Part 2. Kinetic theory

1986 ◽  
Vol 35 (1) ◽  
pp. 75-106 ◽  
Author(s):  
I. J. Donnelly ◽  
B. E. Clancy ◽  
N. F. Cramer
Keyword(s):  
Kinetic Theory ◽  
Wave Equations ◽  
Compressional Wave ◽  
Alfven Wave ◽  
Larmor Radius ◽  
Electrostatic Wave ◽  
Hot Plasma ◽  
Wave Heating ◽  
Ion Cyclotron ◽  
Consequent Increase

Kinetic theory, including ion Larmor radius effects, is used to analyse the Alfvén wave heating of cylindrical plasmas using axisymmetric waves excited by an antenna at frequencies up to the ion cyclotron frequency. At the Alfvén resonance position, the compressional wave is mode converted to a quasi-electrostatic wave (QEW) which propagates towards the plasma centre or edge depending on whether the plasma is hot or warm. The energy absorbed by the plasma agrees with the MHD theory predictions provided the QEW is heavily damped before reaching the plasma centre or edge; if it is not, then QEW resonances may occur with a consequent increase in antenna resistance. The relation between ion cyclotron wave resonances and QEW resonances in a hot plasma is shown. The behaviour described above is demonstrated by numerical solution of the wave equations for small and large tokamak-like plasmas. WKB theory has been used to derive useful expressions which quantify the QEW behaviour.

scholarly journals Collisionless Damping of Fast and Ion?Cyclotron Surface Waves

1993 ◽  
Vol 46 (2) ◽  
pp. 271 ◽  
Author(s):  
GW Rowe
Keyword(s):  
Surface Waves ◽  
Short Wavelength ◽  
Mode Conversion ◽  
Low Frequency ◽  
Wave Mode ◽  
Alfven Wave ◽  
Field Boundary ◽  
First Order ◽  
Vacuum Interface ◽  
Ion Cyclotron

A recently developed general kinetic theory of surface waves is used to calculate the collisionless damping of low frequency fast and ion-cyclotron surface waves on a magnetised plasma-vacuum interface. In particular, the possibility of Cherenkov (Landau and transit-time magnetic) absorption by electrons is accounted for, assuming a bi-Maxwellian distribution of electrons in velocity space. It is shown that in general the surface waves are damped via mode conversion to a short-wavelength mode, such as the kinetic Alfven wave, which is subsequently Landau absorbed within the plasma. For high temperatures this short-wavelength mode can also be radiated into the plasma without being completely absorbed. It is also shown that the related ion-sound surface wave mode and instability identified by Alexandrov et al. (1984) are unphysical, and are the result of neglecting the gas pressure in the first-order magnetic field boundary condition.

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.

Alfvén wave excitation and single-pass ion cyclotron heating in a fast-flowing plasma

2006 ◽  
Vol 13 (5) ◽  
pp. 057103 ◽  
Author(s):  
Akira Ando ◽  
Masaaki Inutake ◽  
Motoi Hatanaka ◽  
Kunihiko Hattori ◽  
Hiroyuki Tobari ◽  
...  
Keyword(s):  
Alfven Wave ◽  
Wave Excitation ◽  
Single Pass ◽  
Ion Cyclotron ◽  
Flowing Plasma

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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