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Astron. Astrophys. 357, 1073-1085 (2000)
9. Conclusions
The main conclusions of the present paper are:
-
Phase mixing of finite-amplitude Alfvén waves in the corona
gives rise to nonlinear coupling of AWs and to spectral energy
redistribution. The strongest coupling in the plasma, which is uniform
along , includes counter-propagating
waves.
-
The nonlinear effects of a non-zero ion Larmor radius on the
finite-amplitude Alfvén waves comes into play at length scales
which are much longer than the dissipation length-scale
. In the coronal holes, the
phase-mixing switches to the nonlinear phase at the heights equal to
10-100 parallel wavelengths , where
the transverse wavelength m while
the dissipation length-scale is
m.
-
Nonlinear coupling introduces a spectral redistribution of the wave
energy, thus changing the rate of the dissipation of wave flux. The
influence of the nonlinear interaction on the actual dissipation of
the wave flux and consequent plasma heating depends on the frequency
of the waves and is a subject of further investigations. The part of
wave energy which is transferred to smaller scales can be damped
rapidly by collisional dissipation.
-
The distance at which the phase-mixing undergoes a transition from
a laminar to a nonlinear stage depends on the wave frequency and
amplitude. In the case of the decay into counterstreaming waves this
distance is proportional to and is
given by (64).
© European Southern Observatory (ESO) 2000
Online publication: June 5, 2000
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