Temperature relaxation in a magnetized plasma

Dong, Chao; Ren, Haijun; Cai, Huishan; Ding, Li

doi:10.1063/1.4827206

Cited by 10 publications

(10 citation statements)

References 31 publications

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“…We also note that, still using the estimates of Ref. [18], the electron-ion temperature relaxation rate scales as ν ei ∼ m e /m i ν i ∼ (m e /m i )ν e , which justifies the fact that it is neglected in the present model. In summary, we have for the various collision processes, in order of importance:…”

Section: Methodssupporting

confidence: 74%

“…For a typical plasma with pedestal parameters T e = T i = 1.5keV, n e = n i = 5 × 10 19 m −3 and L = 30m, we obtain a value ντ ≈ 0.15 by following the approach of Ref. [18] §. It must be noted that, with these parameters, one has λ D /L ≈ 10 −6 , whereas the value used in our simulations is 1000 times larger.…”

Section: Methodsmentioning

confidence: 85%

“…§ Equation (26) in[18] gives the temperature relaxation rate for same-species particles; we used ln Λ = 15 for the Coulomb logarithm.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Effect of collisional temperature isotropisation on ELM parallel transport in a tokamak scrape-off layer

Coulette

Hirstoaga

Manfredi

2016

Plasma Phys. Control. Fusion

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We develop a hybrid model to describe the parallel transport in a tokamak scrape-off layer following an edge-localized mode (ELM) event. The parallel dynamics is treated with a kinetic Vlasov-Poisson model, while the evolution of the perpendicular temperature T ⊥ is governed by a fluid equation. The coupling is ensured by isotropising collisions. The model generalises an earlier approach where T ⊥ was constant in space and time [Manfredi G, Hirstoaga S and Devaux S 2011 Plasma Phys. Control. Fusion 53 015012]. Numerical results show that the main effect comes from electron-electron collisions, which limit the decrease of the parallel electron temperature and increase the potential drop in the Debye sheath in front of the surface. Ion-ion collisions have an almost negligible impact. The net effect is an increased peak power load on the target plates.

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Section: Methodssupporting

confidence: 74%

Section: Methodsmentioning

confidence: 85%

See 1 more Smart Citation

Effect of collisional temperature isotropisation on ELM parallel transport in a tokamak scrape-off layer

Coulette

Hirstoaga

Manfredi

2016

Plasma Phys. Control. Fusion

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“…This theory considers single component plasmas and makes use of a property of adiabatic invariance in a collisions that applies in the extremely magnetized regime (region 4). Other techniques to treat strongly magne- tized plasmas include Fokker-Planck equations [10][11][12][13][14] , binary collisions using perturbation theory 15,16 , generalized Lenard-Balescu theories 17 and guiding-center approximations [18][19][20] .…”

Section: Introductionmentioning

confidence: 99%

A generalized Boltzmann kinetic theory for strongly magnetized plasmas with application to friction

Jose

2020

Physics of Plasmas

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Coulomb collisions in plasmas are typically modeled using the Boltzmann collision operator, or its variants, which apply to weakly magnetized plasmas in which the typical gyroradius of particles significantly exceeds the Debye length. Conversely, O'Neil has developed a kinetic theory to treat plasmas that are so strongly magnetized that the typical gyroradius of particles is much smaller than the distance of closest approach in a binary collision. Here, we develop a generalized collision operator that applies across the full range of magnetization strength. To demonstrate novel physics associated with strong magnetization, it is used to compute the friction force on a massive test charge. In addition to the traditional stopping power component, this is found to exhibit a transverse component that is perpendicular to both the velocity and Lorentz force vectors in the strongly magnetized regime, as was predicted recently using linear response theory. Good agreement is found between the collision theory and linear response theory in the regime in which both apply, but the new collision theory also applies to stronger magnetization strength regimes than the linear response theory is expected to apply in.

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“…Meanwhile, electrons are supposed to have a standard Maxwellian distribution function with temperature T e . It is reasonable since the temperature relaxation rate between electron perpendicular and parallel temperatures is the greatest 32 and the time scale for electron relaxation can be much shorter than the ion time scale 31 , which requires τ ≫ m e /m i . As a result, the ion version of Eq.…”

Section: Equilibriummentioning

confidence: 99%

Geodesic acoustic mode in toroidally rotating anisotropic tokamaks

Ren

2015

Physics of Plasmas

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Effects of anisotropy on the geodesic acoustic mode (GAM) is analyzed by using gyro-kinetic equations applicable to low-frequency microinstabilities in a toroidally rotating tokamak plasma. Dispersion relation in the presence of arbitrary Mach number M , anisotropy strength σ, and the temperature ration τ is analytically derived. It is shown that when σ is less than 3 + 2τ , the increased electron temperature with fixed ion parallel temperature increases the normalized GAM frequency. When σ is larger than 3 + 2τ , the increasing of electron temperature decreases the GAM frequency. The anisotropy σ always tends to enlarge the GAM frequency. The Landau damping rate is dramatically decreased by the increasing τ or σ.

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Temperature relaxation in a magnetized plasma

Cited by 10 publications

References 31 publications

Effect of collisional temperature isotropisation on ELM parallel transport in a tokamak scrape-off layer

Effect of collisional temperature isotropisation on ELM parallel transport in a tokamak scrape-off layer

A generalized Boltzmann kinetic theory for strongly magnetized plasmas with application to friction

Geodesic acoustic mode in toroidally rotating anisotropic tokamaks

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