Aurora caused by energetic proton precipitation into the polar atmosphere

The aurora is a result of energised charged particles (electrons and protons) travelling down the Earth's magnetic field lines and colliding with the neutral atmosphere. The ultimate source of energy for the aurora is the continuous flow of solar wind interacting with the Earth's magnetic field, but how the energy is transferred into the atmosphere is not fully understood. If the energy of auroral particle precipitation is high enough, significant ionisation can occur in the upper-middle atmosphere, which can have important implications for the chemistry and climate of the region.

Most visible aurora is caused by precipitating electrons, but this project will focus on the comparatively poorly understood aurora caused by proton precipitation, which could provide a significant fraction of the energy deposition in the atmosphere. The project will initially test and develop theories for the acceleration mechanisms producing proton aurora. There are several possible directions in which the student could subsequently take the work, including investigating heating of the neutral atmosphere by proton precipitation, possible proton aurora associated with downward electric currents adjacent to an auroral arc, or "shock aurora" caused by a shock front or pressure pulse in the solar wind impacting the Earth.