Special Astrophysics/Space Physics Seminar - Colin Forsythe, Ph.D., UCL Mullard Space Science Laboratory
"The Electric Magnetosphere" by Colin Forsythe, Ph.D., UCL Mullard Space Science Laboratory
Abstract: The deformation of Earth’s magnetic field by its interaction with the solar wind gives rise to a number of electric currents in space. These currents not only define the shape of Earth’s magnetosphere but also allow energy and momentum from the interaction with the solar wind to be coupled to a resistive ionosphere through currents directed along Earth’s magnetic field. Direct evidence for these currents was found early in the space age by measuring magnetic deflections in space, but the complexity, structure and dynamics of these currents remains a challenge in understanding the coupling of the magnetosphere, ionosphere, thermosphere and solar wind. Direct measurement of the currents can be challenging and techniques that rely on Ampere’s law require assumptions that cannot always (if ever) be met. In this talk, I will show how we can use multi-point measurements to examine the field-aligned current systems of the Earth from scales of a few 10s of kilometres up to near global observations and some of the challenges that remain.