1
?.?. ?????, ?.?. ???????, ?.?. ???????? (???
???) ? ??????????? 2 ??????????????? ???????
????????????????? ?????????? ????? ?
????????????? ????????  
2
February 13, 2001, CLUSTER
From EGU06-A-00787Kartalev, M. Savin, S.
Dobreva, P. Amata, E. Shevyrev, N.
From EGU06-A-00787Kartalev, M. Savin, S.
Dobreva, P. Amata, E. Shevyrev, N.
From EGU06-A-00787Kartalev, M. Savin, S.
Dobreva, P. Amata, E. Shevyrev, N.
3
Jets in SW?
BS
MP
4
Wkin
V
X
Y
Z
arcsin(Vy/V)
arcsin(Vz/V)
nVi
MP indentation
5
V, km/s
In most jets nV rises mostly due to n,
for Wk inputs of n and V2 are
comparable
Jets in SW?
VTi
BS
Ni, cm-3
MP
6
- (a) Cluster 3, Wk ram pressure, Wt ion
thermal pressure, Wb magnetic pressure, lagged
Wk in SW (ACE) - (b) Cluster 3, angles
sin-1(Vz/V), sin-1(Vy/V), GDCF model
prediction Insert jet
directions in XZ plane V(-26157) km/s GSE
velocity of the outermost jet as a whole
V(-117-3731) km/s velocity of the innermost
jet. Dashed lines the most deflected jets at
15.03 UT and at 14.97 UT. - (c) comparison of
Wk , keV/cm3, ion density N, 1/cm3, and ion
velocity (V/20, (km/s)/20), Cluster 3 - (d)
the GSE electric component Ey from 4 Clusters




7
Cluster 3, February 13, 2001
Jet inside MP?
Deflected jets with compara-ble input from Ni
and V2 as a probable result of the MSH flow
decay
(-196-23090) km/s (-185106-219)km/s
decay?
Jet going to SW?
630
From magnetic disturbance at leading jet front
Jet width 200 km (2-3) ri
GDCF angle V_XY
8
ISSI book CLUSTER AT THE MAGNETOSPHERIC CUSPS
IMFBzgt0
A summary plot of the Cluster data during the
cusp interval 0500 - 1000 UT on March 17, 2001.
The panels show, from top to bottom, the HIA ion
omni-directional energy fluxes, the HIA ion
density, velocity and temperature, the FGM
magnetic field, all from spacecraft 1, and the
lagged IMF from the ACE spacecraft. (Figure
provided by B. Lavraud)
GSE, 6-12 UT
9
Possible source jet
MP jet
Proxy for MSH
GSE, 6-12 UT
IMFBzgt0
10
Possible source jet
Ion flux nV from Cluster1 on March 17, 2001
(black) versus that of WIND in SW,
(-22-189-40) RE GSM. 1.5nV from WIND would be
a proxy for the ion flux in MSH (with nearly the
same averaged flux 3.3 along the orbit)
MP jet
11
Cluster 1, March 17, 2001
BS jets
Post-BS jets result from density rise. Further in
MSH velocity starts to do comparable input in the
jets flux, slightly dominating at the MP.
Possible source jet
MP jet
12
(No Transcript)
13

• Comparison of B on 4 SC (colors for SC 1-4
  black, blue, violet, red) on March 17, 2001
  associated with the MP jets (see Fig. 1)
• Ram pressure Wk from 3 SC and that of SC1 at
  11.995-12.075 UT (source jet, dashed line,
  lagged)
• Cluster 1 Wk (black), Wt thermal ion pressure
  (blue), Wb magnetic pressure (violet) and Wk in
  SW from Wind (magenta)
• Ey from 4 Clusters.

 




14
60-75 nT
Direction of MP jets versus that of the flow
ahead MP and source one
15
Cluster 1, March 17, 2001
MP jets
2ri
source jet
Vx
Comparison of velocity and density in the
possible source sonic jet (right) with that of
MP supersonic jet (left)
at MP velocity rises and jumps
stronger, density is
slightly less and time-lagged.
Vz
16
(No Transcript)
17
5Ni
30Wk
Vz
Vy
100Wb
BS jets (Y_GSE0)
1st BS
Vx
1st BS
Standing En-wave?
18
Plasma jet interaction with MP
niMiVi2/2 lt k (Bmax)2 /m0 k (0.5-1)
geometric factor niMiVi2/2 gt k (Bmax)2 /m0
The plasma jets, accelerated sunward, often are
regarded as proof for a macroreconnection while
every jet, accelerated in MSH should be
reflected by a magnetic barrier for niMiVi2 lt
(Bmax)2/m0 in the absence of effective
dissipation (that is well known in laboratory
plasma physics)
19
Ms2
magnetosphere
Ms1.2
Wk_SW
MSH
20
(No Transcript)
21
(No Transcript)
22
While the low-latitude reconnection for
the IMF Bzlt0 can account for the jet ram
pressure, it cant do so for the jet direction
as all background energy densities on the jets
paths are negligible versus the jet ram pressure
and magnetic field gradient force is opposite to
that required for the jet rotation
IMF Bzlt0
23
(No Transcript)
24
The energy density pattern on 3 Clusters at 600
km distance is very similar, inferring generally
space structure versus time-dependent disturbances
25
Interball-1, June 19, 1998. (a) Tailward ion
flux nVx from Interball-1, that of Geotail in SW
and gasdynamic proxy (GDCF) Insert jet
directions in XZ GSE plane relative to average MP
and BS
 

26
Shevyrev and Zastenker, 2002
27
In the jets kinetic energy Wkin rises from 5.5
to 16.5 keV/cm3 For a reconnection acceleration
till Alfvenic speed VA it is foreseen WkA ni
VA2 /2 const B2 that requires magnetic field
of 66 nT (120 nT inside MP if averaged with MSH)
Merka, Safrankova, Nemecek, Fedorov,
Borodkova, Savin, Adv. Space Res., 25, No. 7/8,
pp. 1425-1434, (2000)
28
23/04-1998, MHD model, magnetic field at 2230
UT blue Earth field red - SW yellow -
reconnected right bottom slide plasma density
I- Interball-1 G- Geotail P- Polar
Reconnection
X
Reconnection
X
Reconnection
X
Reconnection
X
29
(No Transcript)
30
GSE, 18-24 UT, February 2, 2003
31
Cluster1, February 2, 2003
Cluster3, February 2, 2003
(closer to the Earth)
eV/cc
Supersonic flow
Wb
Wk
Magnetic barrier with sonic flow
Wt
cusp
plasma ball
MP
MP
UT
stagnant turbulent boundary layer
Wb,t,k- cross-correlation lt 0.35
32
(No Transcript)
33
The Alfvenic collapse would stop at the scales of
ion gyroradius (i.e. at the MHD validity
breaking), when magnetic field diffusion due to
the finite ion gyroradius effects can neutralize
the field growth

• For collapse at ion gyroradius scale we estimate
  equilibrium from

We estimate DH from characteristic shift by
squared ion gyroradius ri2 at ion gyroperiod for
the gradient scale ion gyroradius
34

• Interball-1 MSH/stagnation region border
  encounter on April 21, 1996.
• Comparison with switch-off slow shock Karimabadi
  et al., 1995 displays strong magnetic barrier
  with pressure of the order of the MSH ram
  pressure. Inside diamagnetic bubble ion
  temperature balances the external pressure

35
Locations in Geocentric Solar Magnetospheric (GSM)
coordinates of 208 magnetic barriers detected in
Interball-1 magnetic field data between 1995 and
2000.
36
eV/cc
eV/cc
(65-215-82)km/s
(-263-127161)km/s
GSE
Reflected sunward jets (IMF Bzlt0)
Spiraling down the cusp throat (370 to B)
37
reflected from cusp, spiralling upward
reflected from MP jet, spiralling downcusp
38
(No Transcript)
39
(No Transcript)
40
(No Transcript)
41
(No Transcript)
42
Alfven wave filamentation Self-focusing
instability
Bugnon, G., R. Goswami, T. Passot and P.L.
Sulem, TOWARDS FLUID SIMULATIONS OF
DISPERSIVEMHDWAVES IN A WARM COLLISIONLESS
PLASMA, Adv, Space Res., in press (2006)
43
Alfven wave filamentation Self-focusing
instability T. Passot et P.L. Sulem, Landau
fluids for space plasmas
44
Mechanisms for acceleration of plasma jets

• Besides macroreconnection of anti-parallel
  magnetic fields (where the magnetic stress can
  accelerate the plasma till niMiViA2 B2/8p),
  there are experimental evidences for
• Fermi-type acceleration by moving (relative the
  incident flow) boundary of outer boundary layer
• - acceleration at similar boundaries by inertial
  (polarization) drift.

45
Plasma acceleration by pressure gradients at cusp
throat tailward edge
Model Vz in MSH (right) and along Cluster 3
orbit on February 13, 2001 (top, brown curve)
versus Cluster 3 data (blue line) with structured
jets
From EGU06-A-00787Kartalev, M. Savin, S.
Dobreva, P. Amata, E. Shevyrev, N.
46

• Time traces (in microseconds) in turbulent
  boundary layer in tokamak T-10, r34 cm,
• electric field Ep, Volts
• (b) plasma density fluctuations n(t) 1/cm3
• particle flux due to ExB drift across magnetic
  field 1/(cm2 sec)

47
Jet types and generation mechanisms

• (1) BS (just inside, density-produced, cant hit
  MP) Magnetosonic (MS) collapse? Beams/ electric
  standing structures?
• (2) Postshock/MSH - Alfvenic collapse/structuring
  - Decay (deflected jets can
  cross MP and BS )
• - Entropy wave/non-uniform eigen mode?
• - Transformation of BS jets (cant hit
  MP)?
• (3) Transient Decay? Alfvenic collapse/structurin
  g? Cleaning way for moving boundaries?
• (4) Near-MP -(2) -(3) - Reconnection
• - Interaction with reflected waves Savin et
  al., JETPh Lett., 2004
• (a) Local decay of MS waves, amplified by the
  reflected waves
• (b) Inertial drift in standing interference
  structures
• - Pressure gradients at cusp throat (providing
  structured outflow of stagnant plasma along MP
  tailward of the over-cusp indentation)
• - Substructures of secondary shocks/
  discontinuities, cf. (1) ?
• - Oppositely directed normal electric field at
  charged current sheets (first of all MP),
  including moving boundaries (cf. 3)

48
'Plasma jets' are regularly detected in the
magnetosheath (MSH) with preference of occurrence
behind the bow shock (BS). The typical jet
duration is up to several tens of seconds. They
appear intermittently, exhibiting as their main
feature an increase in the dynamic pressure of
2-3 times above the solar wind (SW) pressure.

Jets are seen also in the boundary layers
and even outside the BS. Some of the jets carry
the momentum excess during MSH transition towards
a state of smaller dynamic pressure.
They also appear as a result of transient MSH
reactions on SW disturbances, e.g. cleaning the
way for approaching BS or MP. Transient jets are
followed by decelerated flows having speeds near
or below the Alfvén velocity. The magnetic stress
balance is satisfied in the sub-Alfvénic/Alfvénic
flows, unlike the super-Alfvénic MSH ones. Thus,
the interacting flow-obstacle system would have
lower potential energy after the jets emitting
(this reminds one to a peculiar maser-like
transition from the meta-stable to a stable
state).
49
In the presence of postshock jets the flux in the
middle of MSH tends towards the SW one, which is
in contrast to model predictions. Averaging of
the flux along spacecraft orbits in time gives a
flow deficit of 20-40 with respect to the
gasdynamic model. But averaging in space, taking
into account the jet motion across the spacecraft
at average MSH speed, lets the data and models
converge. Being statistically confirmed, it
suggests that the jets must be considered in the
flow balance of the MSH. Such intermittent/
transient flow concentrations are opposite to the
predictions of gasdynamics and MHD for the
transformation of SW kinetic energy into thermal
energy at the BS since in the jets the dynamic
pressure is rising instead of falling.
We infer supporting of the local energy
conservation by the (quasi) standing in the
obstacle frame electric structures, stored the
energy at intensity maximums in the MSH wave
interference pattern, which re-distributes the
energy of the incident flow.
50
The typical jet velocity approaches the sound
speed in the MSH. Supersonic jets are found in
the mantle/LLBL. Presumably
they are caused by the Laval-nozzle effect. The
high-dynamic pressure jets can skew the MP, being
able to drive secondary reconnection at the
deformed MP. Four jet types are discussed versus
possible mechanisms of their generation,
including inertial drift, Alfven wave
filamentation, 3- wave decay, Alfven
collapse, pressure gradients,
charged current sheets and reconnection. The
reconnection does not seem to be the
dominant jet source even
in boundary layers. The jets occur to be
nonlinear structures detected for decades. But
understanding of their properties and origin
could essentially modify the approach to the SW-
magnetosphere interaction and should also shed
light on heliospheric and astrophysical plasma
streamlinings along withTOKAMAK boundary layers.
This work was supported by INTAS grant
03-50-4872 and ISSI.
51

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