Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the effect of beating during nonlinear frequency chirping   Spectral analyses of energetic particle (EP) driven bursts of MHD
fluctuations in magnetically confined plasmas often exhibit multiple
simultaneous chirps. While the superposition of oscillations at multiple
frequencies necessarily causes beating in the signal acquired by a localized
external probe, self-consistent hybrid simulations of chirping EP modes in a
JT-60U tokamak plasma have demonstrated the possibility of global beating,
where the electromagnetic field vanishes globally between beats and reappears
with opposite phase. This implies that there can be a single field mode that
oscillates at multiple frequencies simultaneously when resonantly driven by
multiple density waves in EP phase space. Conversely, this means that the EP
density waves are mutually coupled and interfere with each other via the
jointly driven field, a mechanism ignored in some theories. In this treatise,
we study the role of field pulsations in general and beating in particular
using the Hamiltonian guiding center orbit-following code ORBIT with a reduced
wave-particle interaction model in realistic geometry. Through amplitude
pulsations and phase jumps, beating is found to drive the evolution of EP phase
space structures. Observations: (1) Beating causes density wave fronts to
advance radially in pulses. The resulting chirps become staircase-like. (2) The
beats facilitate convective transfer of material between neighboring layers of
phase space density waves. On the one hand, this may delay detachment of
solitary vortices. On the other hand, it facilitates the accumulation of hole
and clump fragments into larger structures. (3) Long-range chirping occurs when
massive holes or clumps detach and drift away from the turbulent belt around
the seed resonance. The detached vortices can remain robust and, on average,
maintain their concentric nested layers while being perturbed by the field's
continued beating.

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The categories of this paper are: quant-ph
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The categories of this paper are: cs
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The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
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The categories of this paper are: comp-gas
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The categories of this paper are: supr-con
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The categories of this paper are: gr-qc
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The categories of this paper are: chao-dyn
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The categories of this paper are: plasm-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: q-fin
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The categories of this paper are: math-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-th
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The categories of this paper are: q-bio