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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:0
UID:UW-Physics-Event-6089
DTSTART:20200914T170000Z
DURATION:PT1H0M0S
DTSTAMP:20260415T010649Z
LAST-MODIFIED:20200910T184040Z
LOCATION:VIRTUAL
SUMMARY:Electron Scattering by Low-frequency Whistler Waves at Earthâ€
 ™s Bow Shock\, Plasma Physics (Physics/ECE/NE 922) Seminar\, Mitsuo Ok
 a\, Scientist at Space Sciences Laboratory\, University of California\
 , Berkeley\, CA\, USA
DESCRIPTION:Electrons are accelerated to nonthermal energies at shocks
  in space and astrophysical environments. While shock drift accelerati
 on (SDA) has been considered a key process of electron acceleration at
  Earth’s bow shock\, it has also been recognized that SDA needs to b
 e combined with an additional stochastic process to explain the observ
 ed power-law energy spectra. Here\, we show mildly energetic (∼0.5 k
 eV) electrons are locally scattered (and accelerated while being confi
 ned) by magnetosonic-whistler waves within the shock transition layer\
 , especially when the shock angle is large (θ_Bn > 70 degrees). When 
 measured by the Magnetospheric Multiscale mission at a high cadence\, 
 ∼0.5 keV electron flux increased exponentially in the shock transiti
 on layer. However\, the flux profile was not entirely smooth and the f
 luctuation showed temporal/spectral association with large-amplitude (
 (δB/B ~ 0.3)\, low-frequency (<~ 0.1Ωce where Ωce is the cyclotron 
 frequency)\, obliquely propagating (θ_kB ~ 30 − 60 degrees where θ
 _kB is the angle between the wave vector and background magnetic field
 ) whistler waves\, indicating that the particles were interacting with
  the waves. Particle simulations demonstrate that\, although linear cy
 clotron resonances with ∼0.5 keV electrons are unlikely due to the o
 bliquity and low frequencies of the waves\, the electrons are still sc
 attered beyond 90° pitch angle by coupled nonlinear scattering proces
 ses.<br>
\n <br>
\n*** recurring Zoom meeting for the 922 Seminar in P
 lasma Physics.  This will be valid all semester.  The link is<br>
\n<b
 r>
\nhttps://uwmadison.zoom.us/j/99156107574?pwd=RnA0ZnJHbDdlOHN1dkpFY
 UVYcWZpUT09<br>
\n<br>
\nThe ID and passcode are:<br>
\n<br>
\nMeeting
  ID: 991 5610 7574<br>
\nPasscode: 883688
URL:https://www.physics.wisc.edu/events/?id=6089
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