Particle acceleration and transport in reconnecting magnetic loops

School of Computing, Informatics and Media

University of Bradford

High energy particles and asssociated with them hard X-ray, gamma-ray and ultra-violet emission appearing during a magnetic field reconstruction in solar flares, magnetosphere of interplanetary space produce devastating effect on the Earth atmosphere causing various types of disturbances from shutting communication satellites, power discharges at power stations, producing spectaculare auroras borealis at the polar zones and affecting human wellbeing and health with disrupting variations of the geomagnetic field and high energy radiation migrating from the top of the Earth atmosphere to its surface. This emphasizes the importance of understanding the processes which are responsible for production of these high energy particles and their emission.

In the current project we propose to investigate trajectories, energy and angle distributions of electrons and protons entering 3D reconnecting current sheets with different magnetic field topologies. This will include simulation of particle motion in magnetic topologies in the test particle approach and particle-in-cell (PIC) approach by considering the ambient plasma response to the presence of accelerated particles with the 3V2D code available at Bradford and run in HPC cluster funded by STFC. Magnetic field topologies will be derived from MHD simulations of a few scenarios of magnetic reconnection relevant to solar flares or interplanetary space.

In order to diagnose these accelerated particles in the Sun and interplanetary space, a few energy transport mechanisms inside these loops will be also considered for electrons and protons. This can include some modeling with the modified Fokker-Planck transport codes developed in Bradford of the transport of particles with different charges and mass (electrons and protons) and their diagnosis from high energy emission and by in-situ observations. The project will be run in conjunction with the current RHESSI space satellite providing HXR and gamma ray observations and in anticipation of the future space mission'Solar Orbiter' with the instrument STIX aboard which will measure high energy emission.

Potential PhD student will work in the Space Science Group which has been founded 10 years ago and progressed very well in terms of research and funding from STFC, EPSRC and European Commision. Prof. Zharkova studies particle acceleration and transport in solar flares and interplanetary space, works with data of high energy emission observed by RHESSI, is a co-Investigator on the STIX instrument aboard of the future space mission Solar Orbiter, a lead author of the chapter on theory of particle acceleration in solar flares in the RHESSI era and the author of the monograph on particle acceleration and transport.