HAO Colloquium - Joe Borovsky, Space Science Institute

Solar-Wind/Magnetosphere Coupling: Physics, Statistics, and Systems Science

PHYSICS. Two physical processes are believed to largely control the coupling of the solar wind to the Earth’s magnetosphere: (1) dayside reconnection and (2) the viscous interaction. Based on the Cassak-Shay equation for reconnection rates between plasmas with different properties, solar-wind reconnection driver functions are mathematically derived and tested. Viscous-interaction driver functions are also derived and added to the reconnection driver functions, further increasing the accuracy of mathematically describing the reaction of the magnetosphere-ionosphere system to the solar wind.

STATISTICS. Our ideas about the physics of the solar-wind driving of the magnetosphere are tested via correlations between solar-wind driver functions and geomagnetic indices. But, owing to intercorrelations of the solar-wind variables there is a mathematics-versus-physics dilemma to interpreting the correlations. A blatant example is given. SYSTEMS SCIENCE. Exploiting the problematic solar-wind intercorrelations with the use of canonical correlation analysis, a methodology has been developed to describe the reaction of the magnetosphere to the solar wind with a single aggregate “magnetospheric activity index” that is built upon multiple geomagnetic indices and multiple measures of the magnetosphere. The advantages of this aggregate-index description of the solar-wind-driven magnetosphere are enumerated: one advantage is a very high predictability of the magnetospheric aggregate index from solar-wind variables.

Date and time: 
Wednesday, October 10, 2018 - 2:00pm to 3:00pm
2139 - Capt. Mary