Jack Reid

Much of the Sun's activity is controlled by its global magnetic field, which evolves in response to processes of surface flux transport and to the emergence of new magnetic flux through the photosphere. Using magnetofrictional simulations, which are informed by observational data for the emergence of new flux, I study that evolution, and how it gives rise to various significant magnetic structures in the corona. Especially important are the formation, growth, and eruption of filaments.

Key results from my work include:

• that a magnetograph at the fifth Sun–Earth Lagrange point would substantially improve our capacity to model the growth of filaments on the Earth-facing side of the Sun;
• that the limited field of view from Earth of magnetographs significantly impairs the ability of data-constrained numerical simulations of the solar corona to model the formation of strong magnetic skew at longitudes visible from Earth.

Like many, I work on the coronal heating problem, investigating processes that create and sustain hot temperatures in the Sun's atmosphere. In particular, I study how highly stressed and turbulent magnetic fields give rise to local magnetic instabilities, which can start recurring chains of small, reconnection-triggered heating events—'nanoflares'—that dissipate magnetic energy and cumulatively provide great heating across a range of spatio-temporal scales.

Key results from my work include:

• a detailed analysis of the heating generated by nanoflares in coronal arcades;
• confirming that the heating produced in MHD avalanches can self-consistently sustain coronal conditions against thermodynamic losses;
• establishing the viability of MHD avalanches as a mechanism for coronal heating based on photospheric motions.

Through magnetic reconnection, magnetic field lines 'are broken and re-joined' and the topology of magnetic fields changed. As reconnection is thus instrumental in the evolution of magnetic fields, I explore its onset and effects in MHD plasmas. My work on reconnection has included a focus on the locations at which it occurs in turbulent magnetic fields.

Key results from my work include:

• demonstrating that the squashing factor Q is not a reliable diagnostic for the location of three-dimensional reconnection.