Ion heating in an auroral potential structure
National Observatory of Athens, Institute for Space Applications and Remote Sensing, 15236 Penteli, Greece e-mail: email@example.com
2 Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece e-mail: firstname.lastname@example.org
Corresponding author: A. Anastasiadis, email@example.com
Accepted: 26 February 2004
We investigate the interaction of O+ ions with a one-dimensional potential well, using Hamiltonian formulation. Heating of plasma originating in the terrestrial ionosphere plays a catalytic role in solar-driven magnetic storms, which dissipate energy globally within the magnetosphere of the earth. An interesting candidate for ionospheric plasma heating is a potential well located at auroral arcs in the high-latitude magnetosphere. We consider a potential with an exponential form, having a characteristic length Lx. The oxygen ions drift towards the auroral arc in the presence of a constant magnetic field Bz and a constant electric field Ey. The orbits of individual ions for different initial conditions – phase angle and kinetic energy – are traced. Our results show that, depending upon the initial conditions, test particles can be either accelerated or decelerated. Furthermore, we perform a parametric study for the interactions of mono-energetic and Maxwellian type of initial ion distribution – using random phase angle injection of the particles – with respect to our main model parameter, the characteristic length of the potential Lx. We conclude that for characteristic lengths comparable to twice the ion gyroradius, the O+ population is accelerated.
Key words: acceleration of particles / plasmas
© ESO, 2004