Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pressure-gradient-induced Alfven eigenmodes: II. Kinetic excitation with
  ion temperature gradient   The kinetic excitation of ideal magnetohydrodynamic (MHD) discrete Alfven
eigenmodes in the second MHD ballooning stable domain is studied in the
presence of a thermal ion temperature gradient (ITG), using linear gyrokinetic
particle-in-cell simulations of a local flux tube in shifted-circle tokamak
geometry. The instabilities are identified as alpha-induced toroidal Alfven
eigenmodes (alpha-TAE); that is, bound states trapped between
pressure-gradient-induced potential barriers of the Schroedinger equation for
shear Alfven waves. Using numerical tools, we examine in detail the effect of
kinetic thermal ion compression on alpha-TAEs; both non-resonant coupling to
ion sound waves and wave-particle resonances. It is shown that the Alfvenic ITG
instability thresholds (e.g., the critical temperature gradient) are determined
by two resonant absorption mechanisms: Landau damping and continuum damping.
The numerical results are interpreted on the basis of a theoretical framework
previously derived from a variational formulation. The present analysis of
properties and structures of Alfvenic fluctuations in the presence of steep
pressure gradients applies for both positive or negative magnetic shear and can
serve as an interpretative framework for experimental observations in (future)
high-performance fusion plasmas of reactor relevance.

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The categories of this paper are: patt-sol
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The categories of this paper are: quant-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: cond-mat
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: nlin
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The categories of this paper are: supr-con
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The categories of this paper are: dg-ga
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The categories of this paper are: math
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-ph
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The categories of this paper are: math-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-lat
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The categories of this paper are: acc-phys