Transcript critical_questions

ISSI meeting 31 Mars-04 April
Critical questions and tasks
Organization
• Identified question.
• Possible answers using experimental
data:
• Constraints list
• Expertise available
• Definition of tasks and task coordinator
• Selection of events
• Data sets available
Almost perpendicular
• Crucial issues:
• The data of observations clearly show
the presence of the short scales as
small as several c / ωpe.
• Authors interpretation: Hada-Lembege,
that means the dependence upon “the
NUMBER OF REFLECTED IONS”.
Almost perpendicular – testable features
• Scale independent model:
final solution does not contain other
scale but ion Larmor radius
Strongly dependent upon ion temperature:
nonstationarity does not exist for ion beta
larger than 0.3, electron dynamics has no
any importance
Critical question: potential should become
larger than the energy of almost ALL
upstream flowing particles
Almost perpendicular case –
gradient catastrophe scenario
• Testable features:
• the steepening of the fronts grows, in
terms of experimental data analysis it
will be “scales decrease”
• the localized potential electric field
increase,
• the gradients become larger than some
limit, the overturning occurs
• electron dynamics is important:
adiabatic-non-adiabatic heating
Testable features
• Electric field versus magnetic field
scales
• Small scale electrostatic structures that
can supply up to 20 % - 30 % of the
whole potential jump
• Electric field scales analysis is crucial
• The remark to be addressed to the
simulations: the results will be very
sensitive to the grid size.
Wave activity (common for QPerp and AP)
• Definition of wave modes and their
characteristics (omega – k dependence),
• Shock front generated waves versus
generated by instabilities
• Pointing vector determination (where
possible)
• Events selection
Instabilities associated mechanisms
• Waves identification
• Energy fluxes (Pointing vector)
• Necessary to have long foot and close
to Perp
Almost Perp event for the simulations
QuasiPerp
• Why not to complet 24 of January by
electric field scales, potential, density
and wave energy Pointing vector
having our version of QPerp
• There exists already electric field
statistics for some quasi-perpendicular
Biscamp mechanism
• Wave properties determination
Ripples
• An important issue about almost
tangential crossings where the
« remote features » can appear
Simulations
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Two shocks :
24 January 2001 case
2D –Bertrand, 400 mass ratio, and
Omega_p/ omega_c (2)
Manfred 1D realistic mass ratio (1000)
omega_p/omega_c (10)
• David long system hybrid
• Second shock: small beta, angle close to
90°
• The simulations: two codes (not 2D)