Context. Observations reveal an increase with height of the line width of several coronal spectral lines probably caused by outwardly propagating Alfvén waves. However, the spectral line width sometimes shows a sudden decrease at a height ∼ 0.1–0.2 R⊙, where the ratio of sound to Alfvén speeds may approach unity. Aims. To explain the observed line width reduction in terms of the energy conversi...

In this work we used Particle-In-Cell simulations to study the interaction of circularly polarised Alfvén waves with one dimensional plasma density inhomogeneities transverse to the uniform magnetic field (phase mixing) in collisionless plasmas. In our preliminary work we reported discovery of a new electron acceleration mechanism, in which progressive distortion of the Alfvén wave front, due t...

[1] The gauge condition relating the electromagnetic potentials of shear Alfvén waves is one of the key governing equations in simulations of low-frequency waves in the Earth’s magnetosphere. Mottez [2013] suggests that the gauge condition used in Watt and Rankin [2010] is inappropriate for the case where the perpendicular wave number of the shear Alfvén wave varies as a function of distance al...

Weak Alfvénic turbulence in a periodic domain is considered as a mixed state of Alfvén waves interacting with the two-dimensional (2D) condensate. Unlike in standard treatments, no spectral continuity between the two is assumed, and, indeed, none is found. If the 2D modes are not directly forced, k(-2) and k(-1) spectra are found for the Alfvén waves and the 2D modes, respectively, with the lat...

[1] Using a self‐consistent drift‐kinetic simulation code, we investigate whether electron acceleration owing to shear Alfvén waves in the plasma sheet boundary layer is sufficient to cause auroral brightening in the ionosphere. The free parameters used in the simulation code are guided by in situ observations of wave and plasma parameters in the magnetosphere at distances >4 RE from the Earth....

The usefulness of wavelet analysis is demonstrated by considering analytical expressions for phase mixed Alfvén waves in different physical circumstances. The wavelet analysis is briefly introduced, using the complex-valued Morlet wavelet, consisting of a plane wave modulated by a Gaussian, as the basic wavelet. The time and scale resolution of the wavelet transform are then discussed in more d...

Measurements of intense, localized parallel electric fields are reported in association with inertial Alfvén waves and accelerated electron fluxes in a space plasma. The parallel electric fields are localized to several hundreds of Debye lengths and carry potentials on the order of the energy of the accelerated electron fluxes. The structures are observed at sharp maxima or minima of the pertur...

Abstract Nonlinear interactions involving electrostatic upper-hybrid (UH), ion-cyclotron (IC), lowerhybrid (LH), and Alfvén waves in quantum magnetoplasmas are considered. For this purpose, the quantum hydrodynamical equations are used to derive the governing equations for nonlinearly coupled UH, IC, LH, and Alfvén waves. The equations are then Fourier analyzed to obtain nonlinear dispersion re...

The expansion of a dense (initially, n(lpp)/n(0)>>1) laser-produced plasma into an ambient magnetized plasma ( n(0) = 2 x 10(12) cm(-3)) capable of supporting Alfvén waves has been studied. The interaction results in the production of shear Alfvén waves as well as large density perturbations (Delta n/n(0) approximately 0.3) associated with the moving dense plasma. The waves propagate away from ...

We examine the effect of weak, small scale magnetic field structure on the rate of reconnection in a strongly magnetized plasma. We recover lower and upper limits on the reconnection rate, depending on the reaction of the magnetic field to stresses exerted from within the reconnection layer. Using Goldreich and Sridhar’s model of strong turbulence in a magnetized plasma with negligible intermit...