MP from [Maynard, 2003] -last closed field lines for the northern axis of dipole, deflected by 23 degrees anti-sunward (colored by - |B|)

|B|

Bin

Bout

|B| on MHD model MP

small

large

Magnetosheath (MSH)

niTi + niMi/2(<Vi>2+(<Vi

2>) + |B|2/8

{1} > {2} {3}

Low latitude boundary layer (LLBL)

niTi + niMi/2(<Vi>2+(<Vi

2>) + |B|2/8

{1} > {2} << {3} niMiVA2/2

Turbulent Boundary Layer (TBL) and outer cusp

niTi + niMi/2(<Vi>2+(<Vi

2>)+|B|2/8+|B|2/8

{1} ~ {2} >> {3} < {4}

macro RECONNECTION

Energy transformation in MSH

micro RECONNECTION

Relation of viscous gyro-stress to that of Maxwell:

~ const u / B03

where ru- directed ion gyroradius, and L – the MP width. For ~ 1-10 near MP the viscous gyro-stress is of the order of that of Maxwell. Velocity

u, rises downstream of the subsolar point, magnetic field B0 - has the

minimun over cusp, i.e. the gyroviscous interaction is most significant at the outer border of the cusp, that results in the magnetic flux diffusion

(being equivalent to the microreconnection)

Fx , uFz

BIMF Bin

MSH

magnetosphere

MP

Cluster OT crossing on 2002.02.13

• Quicklook for OT encounter (09:00-09:30 UT) Energetic electrons & ions are seen generally in OT, not in magtosphere, they look to be continuous relative to the lower energy particles. Note also the maximum in energetic electrons at the OT outer border at ~09:35 UT. The upstream energetic particles are seen to 10:30 UT.

|B|

theta

phi

energetic electrons

electrons

energetic ions

ions

OT MSHmagnetospheredipole tilt~14 d

L ~ RE

Surface charge decelerates plasma flow along normal and accelerates it along magnetopause tailward

En

MPMSH cusp

niMiVi2/2 < k (Bmax)2 /0

[k ~ (0.5-1) – geometric factor]

niMiVi2/2 > k (Bmax)2 /0

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 < (Bmax)2/0 in the absence of effective

dissipation (that is well known in laboratory plasma physics)

Plasma jet interaction with MP

Resonance interaction of ions with electrostatic cyclotron waves

Diffusion across the magnetic field can be due to resonance interaction of ions

with electrostatic cyclotron waves

et al.,et al.,

Part of the time, when ions are in resonance with the wave- perpendicular ion energy

that can provide the particle flow

across the southern and northern TBL, which is large across the southern and northern TBL, which is large enough i.e. for populating of the dayside enough i.e. for populating of the dayside magnetospheremagnetosphere

s

Measurements of ion-cyclotron waves on Prognoz-8, 10, Interball-1 in the turbulent boundary layer (TBL) over polar cusps. Maximums are at the proton-cyclotron frequency.

Shown also are the data from HEOS-2 (E=1/c[VxB]), and from the low-latitude MP AMPTE/IRM and ISEE-1.

Estimation of the diffusion coefficient due to electrostatic ion-cyclotron waves demonstrates that the dayside magnetosphere can be populated by the solar plasma through the turbulent boundary layer

Percolation is able to provide the plasma inflow comparable with that due to electrostatic ion cyclotron waves [Galeev et al.,

1985, Kuznetsova & Zelenyi, 1990] : Dp~0.66(B/B0)i

i ~const/B02 ~(5-

10)109 m2/s-----------------------------------------------------------------------------------------------------------------

One can get a similar estimate for the kinetic Alfven waves (KAW in [Hultquist et al., ISSI, 1999, p. 399]):

DKAW~k2i

2Te/Ti VA/k||(B/B0)2~ ~

const/B03 ~ 1010 m2/s

Plasma percolation via the structured magnetospheric

boundary

MSH

magnetosphere

Ion flux

e ~

[Vaisberg, Galeev, Zelenyi, Zastenker, Omel’chenko, Klimov И., Savin et al., Cosmic Researches, 21, p. 57-63, (1983)]

Interpretation of the early data

from Prognoz-8 in terms of the

surface charge at MP

Cluster 1, February 13, 2001. (a) ion flux ‘nVix’, blue

lines – full CIS energy range), black – partial ion flux for > 300 eV, red – for > 1keV ions; (b) the same for ‘nViy’; (c)

the same for ‘nViz’; (d):

ion density ni (blue),

partial ion density for energies > 300 eV (black) and that of > 1 keV (red).

Mass and momentum transfer across MP of finite-gyroradius ion scale ~90 km i at 800 eV

~ along MP normal

dominant flow along MP

1

Cluster 1, February 13, 2001Thin current (TCS) sheet at MP (~ 90 km) is transparent for ions with larger gyroradius, which transfer both parallel and perpendicular momentum and acquire the cross-current potential. The TCS is driven by the Hall current, generated by a part of the surface charge current at the TCS

~300 V

Mechanisms for acceleration of plasma jets

Besides macroreconnection of anti-parallel magnetic fields (where the magnetic stress can accelerate the plasma till niMiViA

2 ~ B2/8), 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.

-Acceleration in the perpendicular non-uniform electric field by the inertial drift

-Fermi-type acceleration by a moving boundary;

Magneto sonic jet

Fl + Fk = FmHz

Bi-coherence & the energy source for the magnetosonic

jet

Inertial drift

Vd(1) = 1/(M H

2) dF/dt = Ze/(M H2) dE/dt

Wkin ~ (nM(Vd(0))2/2) ~ 30 keV/сm3 (28 measured)

Vd(0) = с[ExB] ; J ~ e2/(MpHp

2)dE/dt Electric field in the MSH flow frame

Cherenkov nonlinear resonance

1.4 +3 mHz = fl + f k (kV)/2 ~ 4.4 mHz

L = |V| /( fl + fk )5 RE

Maser-like ?

Comparison of the TBL dynamics and model Lorentz system in the state of intermitten

chaos

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 |B|2

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)]

MSH

magnetosphere

Ms~2

Ms~1.2

[ Shevyrev and Zastenker, 2002 ]

23/04-1998, MHD model, magnetic field at 22:30 UT; blue – Earth field; red - SW; yellow - reconnected; right bottom slide – plasma density; I- Interball-1, G- Geotail; P- Polar X

X

ReconnectionX

Reconnection

Reconnection

The jet is also seen by POLAR (~ 4 Re apart in TBL closer to MP)

BS

MP

- Penetration of solar plasma into magnetosphere correlate with the low magnitude of magnetic field (|B|) (e.g. with outer cusp and antiparallel magnetic fields at MP).

-A mechanism for the transport in this situation is the ‘primary’ reconnection, which releases the energy stored in the magnetic field, but it depends on the IMF and can hardly account for the permanent presence of cusp and low latitude boundary layer. Instead, we outline the ‘secondary’ small-scale time-dependent reconnection.

Other mechanisms, which maximize the transport with falling |B|:- finite-gyroradius effects (including gyro-viscosity and charged current sheets of finite-gyroradius scale, -filamentary penetrated plasma (including jets, accelerated by inertial drift in non-uniform electric fields), -diffusion and percolation, In minimum |B| over cusps and ‘sash’ both percolation and diffusion due to kinetic Alfven waves provide diffusion coefficients ~ (5-10) 109 m2/s, that is enough for populating of dayside boundary layers. Another mechanism with comparable effectiveness is electrostatic ion-cyclotron resonance. While the cyclotron waves measured in the minimum |B| over cusps on Prognoz-8, 10 and Interball-1 have characteristic amplitude of several mV/m, the sharp dependence of the diffusion on |B| provides the diffusion ~ that of the percolation.

Conclusions