Direct Coupling between the Solar Wind and the Thermosphere

Add to your list(s) Download to your calendar using vCal

• George Siscoe, Center for Space Physics, Boston University
• Monday 01 February 2010, 11:00-12:00
• British Antarctic Survey, Room 187.

If you have a question about this talk, please contact Tracy Moffat-Griffin.

When the sun is in an active state and coronal mass ejections reach the top of their speed of ejection and strength of imbedded magnetic field, encounters with Earth subject the thermosphere to direct magnetic coupling to the speeding ejecta with little mediation by the magnetosphere. The force applied to drive thermospheric winds on such occasions is amplified (seemingly paradoxically) an order of magnitude over the force that the solar wind actually exerts. The situation on such occasions differs so markedly from normal that one needs different names to distinguish the normal from the disturbed state. We use “Chapman-Ferraro” and “Dungey-Alfvén,” respectively, for reasons that will be made clear. This is a seminar about the Dungey-Alfvén (DA) situation. The DA state is so rare (~1% of time) that its discovery as a distinct state was possible only with the advent of global numerical simulations, which allow one to isolate it and study it separate from vestiges of the CF state. One of its distinguishing features, as mentioned, is the direct coupling between the solar wind and the thermosphere. We will focus on this coupling, present its properties as revealed by global simulations, explain its paradoxical force, discuss its consequences for thermospheric research, and present evidence for its existence.

This talk is part of the British Antarctic Survey series.

This talk is included in these lists:

• All Talks (aka the CURE list)
• Biology
• British Antarctic Survey
• British Antarctic Survey, Room 187
• Cambridge Environment
• Climate Science Seminars within Cambridge
• Featured lists
• Life Sciences
• Life Sciences
• ME Seminar
• Queens' College Politics Society
• School of Physical Sciences
• Talks related to atmosphere and ocean dynamics and climate science
• my_list
• ob366-ai4er
• other talks

Note that ex-directory lists are not shown.