Proton core heating and beam formation via parametrically unstable Alfvén-cyclotron waves.

Vlasov theory and one-dimensional hybrid simulations are used to study the effects that compressible fluctuations driven by parametric instabilities Alfvén-cyclotron waves have on proton velocity distributions. Field-aligned proton beams are generated during the saturation phase of the wave-particle interaction, with a drift speed which is slightly greater than the Alfvén speed and is maintained until the end of the simulation. The main part of the distribution becomes anisotropic due to phase mixing as is typically observed in the velocity distributions measured in the fast solar wind.

Coronal waves: propagation in the multi-fluid description.

We study wave propagation in the low-beta coronal plasma using a collisionless multi-fluid model. Neglecting the electron inertia, this model allows us to take into account ion-cyclotron wave effects that are absent in the magnetohydrodynamics model. To accomplish this, we perform a Fourier plane-wave perturbation analysis.

Solar wind origin in coronal funnels.

The origin of the solar wind in solar coronal holes has long been unclear. We establish that the solar wind starts flowing out of the corona at heights above the photosphere between 5 megameters and 20 megameters in magnetic funnels. This result is obtained by a correlation of the Doppler-velocity and radiance maps of spectral lines emitted by various ions with the force-free magnetic field as extrapolated from photospheric magnetograms to different altitudes.