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Title: A fully-neoclassical finite-orbit-width version of the CQL3D Fokker–Planck code

Publication Date:
Sponsoring Org.:
OSTI Identifier:
Grant/Contract Number:
FC02-01ER54649; SC0006614; FG02-04ER54744
Resource Type:
Journal Article: Published Article
Journal Name:
Plasma Physics and Controlled Fusion
Additional Journal Information:
Journal Volume: 58; Journal Issue: 11; Related Information: CHORUS Timestamp: 2016-09-09 03:28:12; Journal ID: ISSN 0741-3335
IOP Publishing
Country of Publication:
United Kingdom

Citation Formats

Petrov, Yu V., and Harvey, R. W. A fully-neoclassical finite-orbit-width version of the CQL3D Fokker–Planck code. United Kingdom: N. p., 2016. Web. doi:10.1088/0741-3335/58/11/115001.
Petrov, Yu V., & Harvey, R. W. A fully-neoclassical finite-orbit-width version of the CQL3D Fokker–Planck code. United Kingdom. doi:10.1088/0741-3335/58/11/115001.
Petrov, Yu V., and Harvey, R. W. 2016. "A fully-neoclassical finite-orbit-width version of the CQL3D Fokker–Planck code". United Kingdom. doi:10.1088/0741-3335/58/11/115001.
title = {A fully-neoclassical finite-orbit-width version of the CQL3D Fokker–Planck code},
author = {Petrov, Yu V. and Harvey, R. W.},
abstractNote = {},
doi = {10.1088/0741-3335/58/11/115001},
journal = {Plasma Physics and Controlled Fusion},
number = 11,
volume = 58,
place = {United Kingdom},
year = 2016,
month = 9

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1088/0741-3335/58/11/115001

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  • Within the US Department of Energy/Office of Fusion Energy magnetic fusion research program, there is an important whole-plasma-modeling need for a radio-frequency/neutral-beam-injection (RF/NBI) transport-oriented finite-difference Fokker-Planck (FP) code with combined capabilities for 4D (2R2V) geometry near the fusion plasma periphery, and computationally less demanding 3D (1R2V) bounce-averaged capabilities for plasma in the core of fusion devices. Demonstration of proof-of-principle achievement of this goal has been carried out in research carried out under Phase I of the SBIR award. Two DOE-sponsored codes, the CQL3D bounce-average Fokker-Planck code in which CompX has specialized, and the COGENT 4D, plasma edge-oriented Fokker-Planck code whichmore » has been constructed by Lawrence Livermore National Laboratory and Lawrence Berkeley Laboratory scientists, where coupled. Coupling was achieved by using CQL3D calculated velocity distributions including an energetic tail resulting from NBI, as boundary conditions for the COGENT code over the two-dimensional velocity space on a spatial interface (flux) surface at a given radius near the plasma periphery. The finite-orbit-width fast ions from the CQL3D distributions penetrated into the peripheral plasma modeled by the COGENT code. This combined code demonstrates the feasibility of the proposed 3D/4D code. By combining these codes, the greatest computational efficiency is achieved subject to present modeling needs in toroidally symmetric magnetic fusion devices. The more efficient 3D code can be used in its regions of applicability, coupled to the more computationally demanding 4D code in higher collisionality edge plasma regions where that extended capability is necessary for accurate representation of the plasma. More efficient code leads to greater use and utility of the model. An ancillary aim of the project is to make the combined 3D/4D code user friendly. Achievement of full-coupling of these two Fokker-Planck codes will advance computational modeling of plasma devices important to the USDOE magnetic fusion energy program, in particular the DIII-D tokamak at General Atomics, San Diego, the NSTX spherical tokamak at Princeton, New Jersey, and the MST reversed-field-pinch Madison, Wisconsin. The validation studies of the code against the experiments will improve understanding of physics important for magnetic fusion, and will increase our design capabilities for achieving the goals of the International Tokamak Experimental Reactor (ITER) project in which the US is a participant and which seeks to demonstrate at least a factor of five in fusion power production divided by input power.« less
  • A new three-dimensional relativistic Fokker--Planck code (poloidal angle and two dimensions in momentum space) has been developed for the analysis of electron cyclotron current drive (ECCD) in tokamak plasmas. This numerical code takes into consideration trapped electron effects without using the bounce-average approximation. Simulations have been carried out using the code, and the results were compared with those of a bounce-averaged Fokker--Planck code. There are differences in the current drive efficiencies calculated by the two codes, and this difference is shown to be caused by a change in electron velocity parallel to the magnetic field due to the inhomogeneous magneticmore » field. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.« less
  • The conclusion reached in ref. 1 that the 3-D Fokker-Planck code verses the 2-D bounce-averaged code does not yield the correct current density is prove to be wrong. It is aruged that the results for the 3-D code are very close to those of the 2-D code that employs a bounce-average procedure.(AIP) {copyright} {ital 1996 American Institute of Physics.}
  • CQL3D is a general purpose computer code for modeling auxiliary heating in tokamaks. It calculates the radial distribution of 2D in momentum-space bounce-averaged, ion and electron distribution functions in toroidal geometry, consistent with deposition of rf and/or neutral beam injected power and a diffusive radial transport model. This calculation is carried out with an array of bounce-averaged Fokker-Planck (FP) solvers running on noncircular magnetic flux surfaces, giving the steady-state, toroidally-averaged distribution resulting from a balance between collisions, dc electric field, rf quasilinear diffusion, synchrotron radiation, neutral beam injection, and radial diffusion. CQL3D is coupled to ray-tracing codes for electron cyclotron,more » lower hybrid, and fast waves, to a neutral beam deposition code, and to a noncircular equilibrium code. We describe the code, providing expressions and methodology for calculation of the FP coefficients from each of the constituent processes, and give benchmark applications in order to validate the major components of the code.« less