Cluster 911 Plasmoid

1
Cluster 911 Plasmoid

• Substorm Sept 11, 2002
• DOY 254
• Onset at 1600 UT
• Shock at Cluster 1623
• Plasmoid 1630 - 1740 UT

2
RAPIDdata by Zong

• These remarkable data show that Cluster was in a
  plasmoid (PD) for over 1 hour!
• Trapped fluxes within the plasmoid (a bubble)
• A hurricane or tornado in space !
• What is the source of energy? For tailward flow,
  and particles?
• Here is our chance to look, study

3
Photo by Tom Eklund

• View looking NNW near Tampere, FI
• Just after sunset
• Lake reflections
• Timing not determined
• Beginning of WTS note bright aurora on the left

4
IMAGE data

• Onset occurred at 1600 UT in Finland near KEV or
  KIL
• An isolated substorm
• One auroral arc

5
Cluster position

• At 1600 Cluster at X -19, Y 3, Z -1 in
  the southern lobe
• Low plasma density
• Density rises quickly n 1 cm-3 (CIS) until
  1740
• then falls to n 0.02

6
FGM data

• From 1600 Cluster was in distant plasma sheet
  tailward of the disturbance
• Sharp onset at 1623 UT (see By) may be a shock
• preceeding the plasmoid
• Average tailward velocity of PD after onset 50
  km/s

7
CIS data

• C4 showing high density in the plasmoid

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EFW data

• Electric field
• Fluctuations
• on C4

9
WHISPER dataData by Canu

• Most dramatic emission is at Shock
• Or at the entrance to the plasmoid
• Within PD the noise is fairly unform

10
Taylor et al.JGR Nov 2006

• (Different event))
• Burst of electrons to high energies
• Such bursts are likely involved in WTS and Omega
  band auroras
• It may, or may not, be related to particle
  energization in plasmoid (to be determined)

11
Electric potential contours (plasma flow lines),
the westward traveling surge, electric currents,
auroral bulge Weimer et a., JGR 1994. This
figure puts the WTS in context of the total
activation.
12
Proposed model

• Upper part shows the assumed perturbations
• Lower part shows dJ
• This involved with the induction electric field
• EIND -?A/?t
• This has, in general, components both
  transverse and parallel to B in a realistic
  magnetic field

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3-D view of plasma sheet

• Dusk side has WTS electron precipitation at high
  latitudes
• Morning side has ion precipitation at high
  latitudes
• Reverse at lower latitudes in cyclical order -
  -
• Reaction Newtons third law (e.g. Bursty Bulk
  Flow)

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We can learn from this, for the Earth's
magnetosphere is a cosmic laboratory

• Emslie and Miller 2003 in Dynamic Sun noted
  that Despite decades of observations in
  X-rays and gamma-rays, the mechanism for particle
  acceleration remains an enigma.
• Our suggestion, that this field-aligned electric
  field may be true in general, on a transient
  basis, points out a new approach to energization
  of charged particles in space.
• This is at odds with the current fashions. Parker
  2003, Forward to the same book stated that
• The essential point is that the gas is ionized
  and, therefore, on the large scale of the Sun,
  the gas cannot support any significant electric
  field in its own moving frame of reference.
• Here on Earth, the westward traveling surge at
  the onset of a magnetospheric substorm, is
  similar to solar flares precipitating electrons
  are abruptly energized to about 100 keV
• It all follows from a direct application of
  Maxwells equations, not resorting immediately to
  MHD