Stochastic effects on phase-space holes and clumps in kinetic systems near marginal stability

doi:10.1088/1741-4326/aaa9fd

Title: Stochastic effects on phase-space holes and clumps in kinetic systems near marginal stability

Abstract

The creation and subsequent evolution of marginally-unstable modes have been observed in a wide range of fusion devices. This behaviour has been successfully explained, for a single frequency shifting mode, in terms of phase-space structures known as a 'hole' and 'clump'. Here in this paper, we introduce stochasticity into a 1D kinetic model, affecting the formation and evolution of resonant modes in the system. We find that noise in the fast particle distribution or electric field leads to a shift in the asymptotic behaviour of a chirping resonant mode; this noise heuristically maps onto radial microturbulence via canonical toroidal momentum scattering, affecting hole and clump formation. While the mechanism allowing for the formation of the hole and clump is coherent, the lifetime of a hole and clump is shown to be highly sensitive to initial conditions, affecting the temporal profile of a single bursting event in mode amplitude.

Authors:

^[1];

^[2]; De-Gol, Anthony J. ^[1]; Gorelenkov, Nikolai N. ^[3]; Vann, Roddy G. L. ^[1]

Univ. of York (United Kingdom). York Plasma Inst., Dept. of Physics
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Univ. of Sao Paulo (Brazil). Inst. of Physics
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

Publication Date:: 2018-01-23

Research Org.:: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

Sponsoring Org.:: USDOE; So Paulo Research Foundation

OSTI Identifier:: 1425202

Grant/Contract Number:: AC02-09CH11466; EP/K000225; EP/L01663X; 2012/22830-2

Resource Type:: Accepted Manuscript

Journal Name:: Nuclear Fusion

Additional Journal Information:: Journal Volume: 58; Journal Issue: 8; Journal ID: ISSN 0029-5515

Publisher:: IOP Science

Country of Publication:: United States

Language:: English

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; stochasticity; turbulence; fast ions; hole and clump; nonlinear dynamics; mode chirping; kinetic instabilities

Citation Formats


                    Woods, Benjamin J. Q., Duarte, Vinicius N., De-Gol, Anthony J., Gorelenkov, Nikolai N., and Vann, Roddy G. L. Stochastic effects on phase-space holes and clumps in kinetic systems near marginal stability.  United States: N. p., 2018. 
        Web.  doi:10.1088/1741-4326/aaa9fd.

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                    Woods, Benjamin J. Q., Duarte, Vinicius N., De-Gol, Anthony J., Gorelenkov, Nikolai N., & Vann, Roddy G. L. Stochastic effects on phase-space holes and clumps in kinetic systems near marginal stability.  United States.  doi:10.1088/1741-4326/aaa9fd.

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                    Woods, Benjamin J. Q., Duarte, Vinicius N., De-Gol, Anthony J., Gorelenkov, Nikolai N., and Vann, Roddy G. L. Tue .  
        "Stochastic effects on phase-space holes and clumps in kinetic systems near marginal stability".  United States.  doi:10.1088/1741-4326/aaa9fd.  https://www.osti.gov/servlets/purl/1425202.

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@article{osti_1425202,

  title        = {Stochastic effects on phase-space holes and clumps in kinetic systems near marginal stability},

  author       = {Woods, Benjamin J. Q. and Duarte, Vinicius N. and De-Gol, Anthony J. and Gorelenkov, Nikolai N. and Vann, Roddy G. L.},

  abstractNote = {The creation and subsequent evolution of marginally-unstable modes have been observed in a wide range of fusion devices. This behaviour has been successfully explained, for a single frequency shifting mode, in terms of phase-space structures known as a 'hole' and 'clump'. Here in this paper, we introduce stochasticity into a 1D kinetic model, affecting the formation and evolution of resonant modes in the system. We find that noise in the fast particle distribution or electric field leads to a shift in the asymptotic behaviour of a chirping resonant mode; this noise heuristically maps onto radial microturbulence via canonical toroidal momentum scattering, affecting hole and clump formation. While the mechanism allowing for the formation of the hole and clump is coherent, the lifetime of a hole and clump is shown to be highly sensitive to initial conditions, affecting the temporal profile of a single bursting event in mode amplitude.},

  doi          = {10.1088/1741-4326/aaa9fd},

  journal      = {Nuclear Fusion},

  number       = 8,

  volume       = 58,

  place        = {United States},

  year         = {2018},

  month        = {1}

}

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DOI: 10.1088/1741-4326/aaa9fd

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Cited by: 2 works

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Figures / Tables:

Figure 1: A sketch of a hole and clump on a distribution function peaked near the origin for a chirping, resonant mode interacting with a tokamak plasma. The resonance ω + (m + l_p)ω_θ – nω_φ = 0 undergoes pitchfork bifurcation as the hole and clump move. Stochastic fluctuations modelledmore »

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