THE DISTRIBUTION FUNCTION OF RESONANT IONS AT ION CYCLOTRON HEATING OF PLASMA IN TOKAMAKS

1981 ◽  
pp. 555-559
Author(s):  
V.L. Vdovin
Keyword(s):  
Distribution Function ◽  
Ion Cyclotron

Collisionless evolution of ion distributions in the presence of ion cyclotron resonance heating

1986 ◽  
Vol 36 (3) ◽  
pp. 357-370 ◽  
Author(s):  
D. Anderson ◽  
L.-G. Eriksson ◽  
M. Lisak
Keyword(s):  
Distribution Function ◽  
Analytical Solutions ◽  
Cyclotron Resonance ◽  
Time Development ◽  
Wave Power ◽  
Ion Cyclotron Resonance ◽  
Particle Trapping ◽  
Ion Distributions ◽  
Beam Heating ◽  
Ion Cyclotron

Explicit analytical solutions are given for the collisionless time evolution of the distribution function for ions absorbing RF wave power through ion cyclotron resonance heating in a tokamak. Two different scenarios are considered: (i) conventional ICRH and (ii) combined neutral beam heating and ICRH with the RF wave frequency tuned to the ion cyclotron resonance frequency of the injected ions. Finally, the effect of particle trapping on the time development of the distribution function is also analysed.

Ion Cyclotron Resonance Collision Frequencies of Alkali Ions in Rare Gases

1974 ◽  
Vol 52 (17) ◽  
pp. 1683-1693 ◽  
Author(s):  
M. Riggin
Keyword(s):  
Distribution Function ◽  
Energy Distribution ◽  
Cyclotron Resonance ◽  
Particle Density ◽  
Energy Distribution Function ◽  
Ion Cyclotron Resonance ◽  
Zero Field ◽  
Ion Cyclotron ◽  
Oscillating Electric Field ◽  
Ionic Energy

An ion cyclotron resonance (ICR) spectrometer was used to estimate collision frequencies of K+ and Na+ ions at near thermal velocities in helium and argon gases. The reduced zero field d.c. drift mobilities were found to be 11.4 and 40.7 cm2 PMU1/2/V s for 39K+ in Ar and He respectively and 11.6 and 42.8 cm2 PMU1/2/V s for Na+ in these gases. The effect of ion-neutral collisions on the energy distribution function for ions at resonance with an oscillating electric field is discussed and the average ionic energy as a function of neutral particle density obtained. In deriving the ICR line shape and ionic energy distribution function it is assumed that the mean time between momentum changing collisions is independent of the relative ion–neutral velocity.

Minority-ion distribution function of a plasma under fundamental and second-harmonic ion-cyclotron heating

1995 ◽  
Vol 53 (1) ◽  
pp. 3-23 ◽  
Author(s):  
B. Weyssow
Keyword(s):  
Distribution Function ◽  
Kinetic Equation ◽  
Second Harmonic ◽  
Hermite Polynomials ◽  
Collision Term ◽  
Algebraic Equations ◽  
Ion Temperature ◽  
Ion Distribution ◽  
Ion Cyclotron ◽  
Analytical Result

The distribution function of the minority ions during ion-cyclotron heating is calculated from a kinetic equation composed of a Landau collision term and a surface-averaged quasi-linear heating term. The kinetic equation is solved by a moment method in which the minority-ion distribution function is expanded in irreducible tensorial Hermite polynomials. The coefficients of the expansion are shown to be solutions of a system of coupled algebraic equations, and the effective minority-ion temperature is deduced from a compatibility constraint. The latter equation is in general too complicated to be solved analytically. The distribution function obtained here is therefore a semi-analytical result.

Electrostatic heat flux instabilities

1978 ◽  
Vol 20 (1) ◽  
pp. 47-60 ◽  
Author(s):  
S. Peter Gary
Keyword(s):  
Heat Flux ◽  
Distribution Function ◽  
Electron Beam ◽  
Electron Distribution ◽  
Electron Distribution Function ◽  
High Energy ◽  
Electrostatic Waves ◽  
High Energy Tail ◽  
Ion Acoustic ◽  
Ion Cyclotron

The linear Vlasov dispersion relation for electrostatic waves in a homogeneous plasma is studied for instabilities driven by an electron heat flux. A two Maxwellian model of the electron distribution function gives rise to three unstable modes: the electron beam, ion-acoustic and ion cyclotron heat flux instabilities. At large Te/Ti the ion-acoustic instability has the lowest threshold; at small Te/Ti the electron beam instability is dominant; and at intermediate values of Te/Ti the ion cyclotron mode is the first to go unstable. The presence of a high energy tail on the electron distribution function raises the value of the dimensionless heat flux qe/(nemev3e) at the ion-acoustic threshold, but increasing atomic number of the ions decreases this value.

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