Dependence on ion temperature of shallow-angle magnetic presheaths with adiabatic electrons

Geraldini, Alessandro; Parra, F. I.; Militello, F.

doi:10.1017/s0022377819000771

Dependence on ion temperature of shallow-angle magnetic presheaths with adiabatic electrons

Journal Article · Fri Nov 08 00:00:00 EST 2019 · Journal of Plasma Physics

DOI:https://doi.org/10.1017/s0022377819000771· OSTI ID:1800803

^[1]; Parra, F. I. ^[2]; Militello, F. ^[3]

Univ. of Maryland, College Park, MD (United States); Univ. of Oxford (United Kingdom); Culham Science Centre, Abingdon (United Kingdom). Culham Centre for Fusion Energy (CCFE), EURATOM/UKAEA Fusion Association; OSTI
Univ. of Oxford (United Kingdom)
Culham Science Centre, Abingdon (United Kingdom). Culham Centre for Fusion Energy (CCFE), EURATOM/UKAEA Fusion Association

The magnetic presheath is a boundary layer occurring when magnetized plasma is in contact with a wall and the angle α between the wall and the magnetic field B is oblique. Here, we consider the fusion-relevant case of a shallow-angle, α << 1, electron-repelling sheath, with the electron density given by a Boltzmann distribution, valid for α/$$\sqrt {τ + 1}$$ >> $$\sqrt {m_e/m_i}$$, where m_e is the electron mass, m_i is the ion mass, τ = T_i/ZT_e, T_e is the electron temperature, T_i is the ion temperature, and Z is the ionic charge state. The thickness of the magnetic presheath is of the order of a few ion sound Larmor radii ρ_s = p m_i (ZT_e+ T_i)/ZeB, where e is the proton charge and B = |B| is the magnitude of the magnetic field. We study the dependence on τ of the electrostatic potential and ion distribution function in the magnetic presheath by using a set of prescribed ion distribution functions at the magnetic presheath entrance, parameterized by τ. The kinetic model is shown to be asymptotically equivalent to Chodura’s fluid model at small ion temperature, τ << 1, for | ln α| > 3| ln τ| >> 1. In this limit, despite the fact that fluid equations give a reasonable approximation to the potential, ion gyro-orbits acquire a spatial extent that occupies a large portion of the magnetic presheath. At large ion temperature, τ>> 1, relevant because Ti is measured to be a few times larger than Te near divertor targets of fusion devices, ions reach the Debye sheath entrance (and subsequently the wall) at a shallow angle whose size is given by $$\sqrt α$$ or 1/ $$\sqrt τ$$ , depending on which is largest.

View Accepted Manuscript (DOE)

Research Organization:: University of Maryland, College Park, MD (United States)

Sponsoring Organization:: USDOE Office of Science (SC)

Grant/Contract Number:: FG02-93ER54197

OSTI ID:: 1800803

Journal Information:: Journal of Plasma Physics, Journal Name: Journal of Plasma Physics Journal Issue: 6 Vol. 85; ISSN 0022-3778

Publisher:: Cambridge University PressCopyright Statement

Country of Publication:: United States

Language:: English

References (32)

Particle-in-cell simulations of the plasma-wall transition with a magnetic field almost parallel to the wall Tskhakaya, D.; Kuhn, S. Journal of Nuclear Materials, Vol. 313-316 https://doi.org/10.1016/s0022-3115(02)01548-9	journal	March 2003
Model of a source-driven plasma interacting with a wall in an oblique magnetic field Ahedo, E.; Carralero, D. Physics of Plasmas, Vol. 16, Issue 4 https://doi.org/10.1063/1.3119687	journal	April 2009
Limitations of gyrokinetics on transport time scales Parra, Felix I.; Catto, Peter J. Plasma Physics and Controlled Fusion, Vol. 50, Issue 6 https://doi.org/10.1088/0741-3335/50/6/065014	journal	April 2008
Kinetic simulations of the Chodura and Debye sheaths for magnetic fields with grazing incidence Coulette, David; Manfredi, Giovanni Plasma Physics and Controlled Fusion, Vol. 58, Issue 2 https://doi.org/10.1088/0741-3335/58/2/025008	journal	January 2016
Gyrokinetic treatment of a grazing angle magnetic presheath Geraldini, A.; Parra, F. I.; Militello, F. Plasma Physics and Controlled Fusion, Vol. 59, Issue 2 https://doi.org/10.1088/1361-6587/59/2/025015	journal	January 2017
Solution to a collisionless shallow-angle magnetic presheath with kinetic ions Geraldini, A.; Parra, F. I.; Militello, F. Plasma Physics and Controlled Fusion, Vol. 60, Issue 12 https://doi.org/10.1088/1361-6587/aae29f	journal	October 2018
Principles of Plasma Discharges and Materials Processing Lieberman, Michael A.; Lichtenberg, Allan J. https://doi.org/10.1002/0471724254	book	January 2005
The Magnetised Plasma-Wall Transition: Theory and PIC Simulation Tskhakaya, D.; Kuhn, S. Contributions to Plasma Physics, Vol. 44, Issue 56 https://doi.org/10.1002/ctpp.200410081	journal	September 2004
Particle-in-cell simulations of the plasma-wall transition with a magnetic field almost parallel to the wall Tskhakaya, D.; Kuhn, S. Journal of Nuclear Materials, Vol. 313-316 https://doi.org/10.1016/S0022-3115(02)01548-9	journal	March 2003
Drift Instabilities in General Magnetic Field Configurations Rutherford, P. H. Physics of Fluids, Vol. 11, Issue 3 https://doi.org/10.1063/1.1691954	journal	January 1968
Boundary conditions for plasma fluid models at the magnetic presheath entrance Loizu, J.; Ricci, P.; Halpern, F. D. Physics of Plasmas, Vol. 19, Issue 12 https://doi.org/10.1063/1.4771573	journal	December 2012
Finite ion temperature effects on scrape-off layer turbulence Mosetto, Annamaria; Halpern, Federico D.; Jolliet, Sébastien Physics of Plasmas, Vol. 22, Issue 1 https://doi.org/10.1063/1.4904300	journal	January 2015
Ion energy-angle distribution functions at the plasma-material interface in oblique magnetic fields Khaziev, Rinat; Curreli, Davide Physics of Plasmas, Vol. 22, Issue 4 https://doi.org/10.1063/1.4916910	journal	April 2015
Models, assumptions, and experimental tests of flows near boundaries in magnetized plasmas Siddiqui, M. Umair; Thompson, Derek S.; Jackson, Cory D. Physics of Plasmas, Vol. 23, Issue 5 https://doi.org/10.1063/1.4943523	journal	March 2016
Sheath structure in a magnetized plasma Holland, D. L.; Fried, B. D.; Morales, G. J. Physics of Fluids B: Plasma Physics, Vol. 5, Issue 6 https://doi.org/10.1063/1.860806	journal	June 1993
Kinetic equations for low frequency instabilities in inhomogeneous plasmas Antonsen, Thomas M.; Lane, Barton Physics of Fluids, Vol. 23, Issue 6 https://doi.org/10.1063/1.863121	journal	January 1980
Nonlinear gyrokinetic equations for low-frequency electromagnetic waves in general plasma equilibria Frieman, E. A. Physics of Fluids, Vol. 25, Issue 3 https://doi.org/10.1063/1.863762	journal	January 1982
Plasma–wall transition in an oblique magnetic field Chodura, R. Physics of Fluids, Vol. 25, Issue 9 https://doi.org/10.1063/1.863955	journal	January 1982
Theory of the collisional presheath in an oblique magnetic field Riemann, K. ‐U. Physics of Plasmas, Vol. 1, Issue 3 https://doi.org/10.1063/1.870800	journal	March 1994
Effect of magnetic field on the distribution of ions striking a planar target Parks, P. B.; Lippmann, S. I. Physics of Plasmas, Vol. 1, Issue 12 https://doi.org/10.1063/1.870926	journal	December 1994
Structure of the plasma-wall interaction in an oblique magnetic field Ahedo, E. Physics of Plasmas, Vol. 4, Issue 12 https://doi.org/10.1063/1.872606	journal	December 1997
Particle trajectories in a sheath in a strongly tilted magnetic field Cohen, R. H.; Ryutov, D. D. Physics of Plasmas, Vol. 5, Issue 3 https://doi.org/10.1063/1.872764	journal	March 1998
Kinetic analysis of the plasma boundary layer in an oblique magnetic field Daube, Th.; Riemann, K. -U. Physics of Plasmas, Vol. 6, Issue 6 https://doi.org/10.1063/1.873512	journal	June 1999
The Bohm criterion and sheath formation Riemann, K. -U Journal of Physics D: Applied Physics, Vol. 24, Issue 4 https://doi.org/10.1088/0022-3727/24/4/001	journal	April 1991
Chapter 4: Power and particle control Loarte, A.; Lipschultz, B.; Kukushkin, A. S. Nuclear Fusion, Vol. 47, Issue 6 https://doi.org/10.1088/0029-5515/47/6/S04	journal	June 2007
Stability of general plasma equilibria - I formal theory Taylor, J. B.; Hastie, R. J. Plasma Physics, Vol. 10, Issue 5 https://doi.org/10.1088/0032-1028/10/5/301	journal	January 1968
Linearized gyro-kinetics Catto, P. J. Plasma Physics, Vol. 20, Issue 7 https://doi.org/10.1088/0032-1028/20/7/011	journal	July 1978
Principles of Plasma Diagnostics: Second Edition Hutchinson, I. H. Plasma Physics and Controlled Fusion, Vol. 44, Issue 12 https://doi.org/10.1088/0741-3335/44/12/701	journal	November 2002
Transport of vacuum arc plasmas through magnetic macroparticle filters Anders, A.; Anders, S.; Brown, I. G. Plasma Sources Science and Technology, Vol. 4, Issue 1 https://doi.org/10.1088/0963-0252/4/1/001	journal	February 1995
One-dimensional plasma sheath model in front of the divertor plates Tskhakaya, D. Plasma Physics and Controlled Fusion, Vol. 59, Issue 11 https://doi.org/10.1088/1361-6587/aa8486	journal	September 2017
The Plasma Boundary of Magnetic Fusion Devices Stangeby, Peter C. Plasma Physics and Controlled Fusion, Vol. 43, Issue 2 https://doi.org/10.1887/0750305592	book	January 2000
Spacecraft Electric Propulsion-An Overview Martinez-Sanchez, M.; Pollard, J. E. Journal of Propulsion and Power, Vol. 14, Issue 5 https://doi.org/10.2514/2.5331	journal	September 1998

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