Alpha-particle loss-cone-type instability in steady-state tokamaks

1981 ◽  
Vol 62 (1) ◽  
pp. 164-174
Author(s):  
G. Malescio
Keyword(s):  
Steady State ◽  
Alpha Particle ◽  
Loss Cone ◽  
Particle Loss ◽  
Cone Type

An Alpha Particle Distribution Function for Mirror Loss-Cone Type Instability Calculations

1986 ◽  
Vol 10 (3P2B) ◽  
pp. 1171-1176 ◽  
Author(s):  
S.K. Ho ◽  
G.R. Smith ◽  
W.M. Nevins ◽  
G.H. Miley
Keyword(s):  
Distribution Function ◽  
Alpha Particle ◽  
Particle Distribution ◽  
Particle Distribution Function ◽  
Loss Cone ◽  
Cone Type

Electromagnetic cyclotron-loss-cone instability associated with weakly relativistic electrons

1982 ◽  
Vol 28 (3) ◽  
pp. 503-525 ◽  
Author(s):  
H. K. Wong ◽  
C. S. Wu ◽  
F. J. Ke ◽  
R. S. Schneider ◽  
L. F. Ziebell
Keyword(s):  
Cyclotron Frequency ◽  
Maximum Growth ◽  
Basic Mechanism ◽  
Electron Cyclotron ◽  
Relativistic Electrons ◽  
Electron Component ◽  
Loss Cone ◽  
Electron Cyclotron Frequency ◽  
Cone Type ◽  
Consistent Manner

The amplification of fast extraordinary mode waves with frequencies very close to the electron cyclotron frequency is investigated for a plasma which consists of a weakly relativistic electron component with a loss-cone type distribution and a cold background electron component. The basic mechanism of the amplification is attributed to a relativistic cyclotron resonance between the wave and the energetic electrons. The method employed in the present analysis enables us to solve the dispersion relation in a self-consistent manner for arbitrary ratio of the densities of the energetic and background electrons. It is found that the maximum growth rates occur at certain values of ω2pe/Ω2e and the angular dependence of the growth rate is sensitive to the ratios ω2pe/Ω2e and ne/nb. Here ωpe and Ωe are the electron plasma frequency and the electron cyclotron frequency, respectively, and ne and nb denote the number densities of the energetic and background electrons, respectively.

scholarly journals Accelerated methods for direct computation of fusion alpha particle losses within, stellarator optimization

2020 ◽  
Vol 86 (2) ◽  
Author(s):  
Christopher G. Albert ◽  
Sergei V. Kasilov ◽  
Winfried Kernbichler
Keyword(s):  
Alpha Particle ◽  
Symplectic Integrators ◽  
Particle Loss ◽  
Early Classification ◽  
Statistical Computation ◽  
Computational Speed ◽  
Order Of Magnitude ◽  
Speed Up ◽  
Orbit Types ◽  
Optimization Loop

Accelerated statistical computation of collisionless fusion alpha particle losses in stellarator configurations is presented based on direct guiding-centre orbit tracing. The approach relies on the combination of recently developed symplectic integrators in canonicalized magnetic flux coordinates and early classification into regular and chaotic orbit types. Only chaotic orbits have to be traced up to the end, as their behaviour is unpredictable. An implementation of this technique is provided in the code SIMPLE (symplectic integration methods for particle loss estimation, Albert et al., 2020b, doi:10.5281/zenodo.3666820). Reliable results were obtained for an ensemble of 1000 orbits in a quasi-isodynamic, a quasi-helical and a quasi-axisymmetric configuration. Overall, a computational speed up of approximately one order of magnitude is achieved compared to direct integration via adaptive Runge–Kutta methods. This reduces run times to the range of typical magnetic equilibrium computations and makes direct alpha particle loss computation adequate for use within a stellarator optimization loop.

Resonant electron diffusion as a saturation process of the synchrotron maser instability

1986 ◽  
Vol 35 (1) ◽  
pp. 177-184
Author(s):  
M. C. Lee ◽  
S. P. Kuo
Keyword(s):  
Electron Distribution ◽  
Loss Cone ◽  
Electron Diffusion ◽  
Linear Diffusion ◽  
Saturation Process ◽  
Auroral Kilometric Radiation ◽  
Cone Type ◽  
Resonant Electron ◽  
Effective Saturation ◽  
Calculated Intensity

The theory of resonant electron diffusion as an effective saturation process of the auroral kilometric radiation has been formulated. The auroral kilometric radiation is assumed to be amplified by the synchrotron maser instability that is driven by an electron distribution of the loss-cone type. The calculated intensity of the saturated radiation is found to have a significantly lower value in comparison with that caused by the quasi-linear diffusion process as an alternative saturation process. This indicates that resonant electron diffusion dominates over quasi-linear diffusion in saturating the synchrotron maser instability.

scholarly journals Measurements of DT alpha particle loss near the outer midplane of TFTR

1995 ◽  
Vol 35 (12) ◽  
pp. 1445-1455 ◽  
Author(s):  
S.J Zweben ◽  
D.S Darrow ◽  
H.W Herrmann ◽  
M.H Redi ◽  
J.F Schivell ◽  
...  
Keyword(s):  
Alpha Particle ◽  
Particle Loss

scholarly journals Measurements of DT alpha particle loss near the outer midplane of TFTR

10.2172/91935 ◽  
1995 ◽  
Author(s):  
S.J. Zweben ◽  
D.S. Darrow ◽  
H.W. Herrmann ◽  
M.H. Redi ◽  
J. Schivell ◽  
...  
Keyword(s):  
Alpha Particle ◽  
Particle Loss
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