Science Seminars

4/9/2009 – Is Jupiter’s magnetosphere fundamentally different than Earth’s?

Speaker: Peter Delamere, LASP
Date: Thursday, Apr 09, 2009
Time: 4:00pm
Location: LSTB 299

Seminar Abstract:

Following the New Horizons’ encounter with Jupiter, there has been a flurry of debate in the literature regarding the fundamental nature of Jupiter’s magnetosphere. The observation of large plasmoids filling Jupiter’s magnetotail prompted the suggestion by McComas and Bagenal [2007] that Jupiter has “a fundamentally different interaction with the solar wind”. At Earth, there is abundant evidence of fundamental differences in magnetospheric configuration during periods of southward-directed and northward-directed interplanetary magnetic field (IMF). One of the dramatic signatures of solar wind energy input during southward IMF is the so-called auroral substorm. But a key difference at Jupiter is the addition of an internal plasma source from Io’s prodigious volcanic activity. The internal plasma source combined with the centrifugal stresses of this rapidly rotating (i.e. 10 hour period) gas giant leads to the generation of Jupiter’s internally-driven main auroral oval. The basic question, then, is what role does the solar wind play in the dynamics of the outer magnetosphere and the generation of Jupiter’s polar aurora? Much of the debate centers on the relative importance of Dungey-like convection vs. an Axford and Hines-like convection. We will compare Earth and Jupiter and show that one magnetosphere’s meat might be another magnetosphere’s poison.