Interaction of energetic particles with waves in strongly inhomogeneous solar wind plasmas

Journal Article · Sun Dec 01 04:00:00 EST 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/778/2/111· OSTI ID:22341952

Krafft, C. ^[1]; Volokitin, A. S. ^[2]

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1. Laboratoire de Physique des Plasmas, Ecole Polytechnique, F-91128 Palaiseau Cedex (France)
2. Space Research Institute, 84/32 Profsoyuznaya Str., 117997 Moscow (Russian Federation)

Observations performed in the solar wind by different satellites show that electron beams accelerated in the low corona during solar flares can propagate up to distances around 1 AU, that Langmuir waves' packets can be clumped into spikes with peak amplitudes three orders of magnitude above the mean, and that the average level of density fluctuations can reach several percents. A Hamiltonian model is built describing the properties of Langmuir waves propagating in a plasma with random density fluctuations by the Zakharov's equations and the beam by means of particles moving self-consistently in the fields of the waves. Numerical simulations, performed using parameters relevant to solar type III conditions at 1 AU, show that when the average level of density fluctuations is sufficiently low, the beam relaxation and the wave excitation processes are very similar to those in a homogeneous plasma and can be described by the quasilinear equations of the weak turbulence theory. On the contrary, when the average level of density fluctuations overcomes some threshold depending on the ratio of the thermal velocity to the beam velocity, the plasma inhomogeneities crucially influence the characteristics of the Langmuir turbulence and the beam-plasma interaction.

• OSTI ID: 22341952
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 778; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
AMPLITUDES
COMPUTERIZED SIMULATION
DENSITY
DISTANCE
ELECTRON BEAMS
EQUATIONS
EXCITATION
FLUCTUATIONS
HAMILTONIANS
HOMOGENEOUS PLASMA
INSTABILITY
INTERACTIONS
RANDOMNESS
RELAXATION
SOLAR FLARES
SOLAR WIND
SUN
TURBULENCE
VELOCITY
WAVE PACKETS