New, simplified technique for calculating particle source rates due to neutral beam injection into tokamaks

Feng, Y.; Wolle, B.; Hübner, K.

doi:10.1016/0010-4655(95)00013-6

Cited by 27 publications

(30 citation statements)

References 12 publications

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“…The high accuracy of these codes has, however, to be paid with relatively intensive numerical efforts, which compromises their use in real-time applications. In addition, there are reduced models like FIFPC [11], SINBAD-SSFPQL [12][13][14], RISK [15], CQL3D [16][17][18]. However, also these models are not optimized for real-time applications.…”

Section: Introductionmentioning

confidence: 99%

RABBIT: Real-time simulation of the NBI fast-ion distribution

et al. 2018

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A novel code is presented, which is capable of computing the NBI fast-ion distribution in real-time. We discuss the approximations needed to arrive at this goal: A simplified beam geometry is used for calculating the beam attenuation. Finiteorbit-width effects are taken into account by an orbit average of the beam deposition. The time-dependent solution of the Fokker-Planck equation (2D in velocity) is then calculated based on analytic expressions. This code currently takes ≈25 ms per time step, which is roughly a factor of 1000 faster than the more sophisticated NUBEAM code. Nevertheless, good agreement between both codes is found in a comprehensive benchmark.

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Section: Introductionmentioning

confidence: 99%

RABBIT: Real-time simulation of the NBI fast-ion distribution

et al. 2018

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“…SINBAD [32] is a fast and accurate NBI code based on a "narrow-beam" model, which takes into account the geometry of the injectors, and the divergence and/or focusing of the beams. The NBI deposition profiles are evaluated as function of the velocity pitch angle and expanded in Legendre polynomials as required by SSFPQL.…”

Section: The Neutral Beam Injection Sourcementioning

confidence: 99%

“…This output, however, is very noisy, and information is lost in the smoothing process required to use it in a kinetic code like SSFPQL. As a more convenient alternative, the multiple-beam NBI code SINBAD [32] has been extended to accept arbitrary numerical tokamak equilibria, and inserted as a module in SSFPQL.…”

Section: Introductionmentioning

confidence: 99%

Simulations of combined neutral beam injection and ion cyclotron heating with the TORIC-SSFPQL package

et al. 2011

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Abstract.A source describing the injection of fast ions due to the ionization of high-energy neutral beams has been added to the surface-averaged quasilinear Fokker-Planck code SSFPQL (M. Brambilla 1994 Nuclear Fusion 34 1121). For this purpose, the multiplebeam NBI code SINBAD (Y. Feng et al. 1995, Comp. Phys. Comm. 88 161) has been included as a module in SSFPQL, with the modifications required to handle arbitrary axisymmetric equilibria. Alternatively, the Neutral Beam Injection (NBI) source can be built using the output of a Monte Carlo NBI code. We have also added a term describing losses of fast ions during thermalization, and a subroutine evaluating the neutron production rate by nuclear reactions. With these extensions, iterations between SSFPQL and the full-wave solver TORIC (M. Brambilla 1999 Plasma Phys. Control. Fusion 41 1) can now be used to investigate the strong interplay between NBI and Ion Cyclotron (IC) heating. By comparing the predicted and measured neutron production rates from D-D reactions in a discharge with combined NBI and IC heating in ASDEX Upgrade we obtain a plausible estimate of the importance of fast ion losses, even if their cause cannot be identified. We find, however, that the plasma composition, in particular the presence low Z impurities, plays a more critical role than fast ion losses in limiting the efficiency of this heating scheme.

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“…The distributions in energy are extremely narrow, and for the present aim well described by Dirac-delta functions. The radial and pitch-angle distributions S i,k (ψ, µ), on the other hand, are calculated by codes either based on a pencil beam model [3] or using a Monte Carlo approach [4]. In this work we use the particle source rates calculated by the Monte Carlo code FAFNER [5].…”

Section: -Nbi Source In Ssfpqlmentioning

confidence: 99%

Simulations of NBI-ICRF synergy with the full-wave TORIC package

Bilato

Brambilla

Horton³

et al. 2009

AIP Conference Proceedings

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Abstract. During the combined plasma heating with neutral beam injection (NBI) and waves in the ion cyclotron (IC) range of frequencies, the NBI fast ions are preferentially accelerated by IC waves close to the IC harmonics, as a consequence of finite Larmor radius (FLR) effects. Since the NBI fast ions are expected to have a strong influence on the wave absorption and propagation, we have implemented a NBI source in the quasilinear Fokker-Planck SSFPQL code, interfaced with the toroidal full-wave TORIC solver. In this implementation the NBI ionization sources are obtained from the output of a Monte Carlo code, such as FAFNER. The numerical scheme adopted in the TORIC-SSFPQL package allows to describe very anisotropic sources, such as NBI, and to iterate the solution of Maxwell's equation taking into account selfconsistently the fast ion tails. As a first application, we present modeling of an ASDEX-Upgrade discharge with combined NBI and ICRF heating. Keywords -Introduction. Neutral beam injection (NBI) and damping of fast waves (FW) inthe ion cyclotron (IC) range of frequencies are the standard methods of ion heating in magnetically confined plasmas. The combination of NBI and IC heating can produce high-energy ion tails. In present day devices, this can be used to address the physics of fast ions [1]. There is a close interplay between the formation of fast-ion tails and the propagation and absorption of IC waves. Numerical simulations of IC heating, therefore, require a self-consistency loop between a wave solver and a solver of the kinetic Fokker-Planck (FP) equation. In view of this, the full wave code TORIC has been recently modified to evaluate the coefficients of the wave equations with the ion distribution functions (DFs) calculated by FP solver SSFPQL, which, in turn, takes into account the quasilinear power source due to the radio-frequency (RF) waves [2]. At IC harmonics (ω = n Ω ci with n ≥ 2) ion heating is a finite Larmor radius (FLR) effect, and, therefore, preferentially accelerates ions with large Larmor radius, ρ k ⊥ > ∼ 1 with k ⊥ the perpendicular wave number, and ρ = v ⊥ /Ω ci . When NBI and harmonic IC heating are simultaneously present, therefore, rather strong synergetic effects can be expected. To simulate this situation, we have now extended SSFPQL to include the NBI source in the FP equation, as we briefly describe in the next section. In the last section we present the results of a first application to an ASDEX-Upgrade (AUG) discharge. -NBI source in SSFPQL.With simultaneous NBI and RF heating the steady-state quasilinear kinetic equation for ion species i is

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New, simplified technique for calculating particle source rates due to neutral beam injection into tokamaks

Cited by 27 publications

References 12 publications

RABBIT: Real-time simulation of the NBI fast-ion distribution

RABBIT: Real-time simulation of the NBI fast-ion distribution

Simulations of combined neutral beam injection and ion cyclotron heating with the TORIC-SSFPQL package

Simulations of NBI-ICRF synergy with the full-wave TORIC package

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