Dispersive ionospheric Alfvén resonator

Propagation of kinetic Alfvén waves in the ionospheric Alfvén resonator in the presence of density cavities

[1] Recent observations of particle distributions that are narrow in pitch angle and broad in energy have suggested that kinetic Alfvén waves are a significant contributor to auroral particle acceleration. Oscillations at frequencies near 1 Hz are a natural consequence of the propagation of Alfvén waves in the strongly varying Alfvén speed profile above the auroral ionosphere, the so-called ion...

Non-local interactions between electrons and Alfvén waves on auroral field lines

The interaction of auroral electrons with kinetic Alfvén waves is complicated by the fact that the Alfvén speed above the ionosphere is strongly inhomogeneous, leading to a region often referred to as the ionospheric Alfvén resonator (IAR). For these waves, the wave-particle interaction must be treated with a non-local kinetic approach. Linear damping of these waves due to the wave-particle int...

CHAMP observation of intense kilometer-scale field-aligned currents, evidence for an ionospheric Alfvén resonator

Bursts of very intense kilometer-scale fieldaligned currents (KSFACs) are observed quite frequently by the CHAMP satellite when passing through the auroral region. In extreme cases estimated current densities exceed 3 mA/m2. Typical scale sizes of these KSFACs are 1 km. The low-Earth, polar orbiting satellite CHAMP allows one to assess KSFACs down to scales of a couple of 100 m based on its hig...

In ̄uence of the ®nite ionospheric conductivity on dispersive, nonradiative ®eld line resonances

The in ̄uence of the ®nite ionospheric conductivity on the structure of dispersive, nonradiative ®eld line resonances (FLRs) is investigated for the ®rst four odd harmonics. The results are based on a linear, magnetically incompressible, reduced, twōuid MHD model. The model includes e€ects of ®nite electron inertia (at low altitude) and ®nite electron pressure (at high altitude). The ionosphere ...

Comment on ‘ ‘ Role of dispersive Alfvén waves in generating parallel electric fields along the Io - Jupiter fluxtube ’ ’ by S .