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SUMMARY:Alfvén Eigen-modes\, Turbulent Transport  and Storms in near-Eart
 h Space
DTSTART:20150706T140000
DTSTAMP:20260510T062935Z
UID:2312b12b2716809c39ee7afc2f4082ca5ff45bc5ecd2f8dbe768264e
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. C.C. Chaston\n(with acknowledgement to NASA’s Van Alle
 n Probes and THEMIS mission teams)\n(Space Sciences Laboratory University 
 of California\, Berkeley\, CA 94720\, USA  and\nSchool of Physics\, Unive
 rsity of Sydney\, NSW 2006\, Australia)\nThe impact of explosive mass ejec
 tions from the Sun on the Earth drive major disturbances of our near space
  environment called Geomagnetic Storms. These storms present a significant
  hazard to ground and space based infrastructure vital to our present day 
 way of life. From the bombardment of spacecraft by energetic particles to 
 the induction of catastrophic currents in power-lines\, geomagnetic storms
  can lead to the loss of vital communication links and power distribution 
 networks with debilitating effect. Despite more than 50 years of study how
 ever predicting the evolution and geo-effectiveness of an individual storm
  remains problematic – this is due to the complexity of the particle acc
 eleration process and because the manner through which large scale electri
 c currents and fields are generated and structured during storms is not we
 ll understood. A new two spacecraft plasma physics mission to Earth’s in
 ner magnetosphere has allowed the discovery of very large amplitude broadb
 and electromagnetic fluctuations that are invariably present during the ma
 in phase of geomagnetic storms. In this presentation I describe the proper
 ties of these variations and show how they correspond to the accumulation 
 of energy in kinetic scale Alfvén Eigen-modes of the geomagnetic field. I
 t is shown how these modes are driven by impulsive plasma injections due t
 o magnetic reconnection in Earth’s geomagnetic tail.  It is shown how t
 hese modes act to ‘pump-up’ ion energy density in Earth’s inner magn
 etosphere during storms. It is shown from observations how this process ma
 y distort the geomagnetic field and thereby alter the drift paths of all p
 lasmas populating the near-Earth space environment including those of the 
 radiation belts. This global effect may account for certain enigmatic feat
 ures of the storm-time magnetosphere. This new discovery introduces physic
 s not often considered in the magnetospheric context but is perhaps well k
 nown in tokamaks. Some relevant comparisons will be made.
LOCATION:PPB 019
STATUS:CONFIRMED
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