Признаки стационарного магнитного пересоединения в...

Признаки стационарного магнитного пересоединения в

солнечном ветреЮ. Л. Сасунов, В. С. Семенов

СС. Петербургский университет

Thanks to N. Erkaev, M. Heyn,H. Biernat and I. Kubyshkin

Sites for reconnection in magnetosphere

“Standard Model” of Flares

Reconnection at the Leading Edge of an ICME

After J. Gosling

Results from Study of Initial 49 Exhausts Identified in the ACE 64-s Data (~1.3 events/month)

Most of the exhausts were associated with relatively large field shear angles.

Typical exhaust crossing times were 10 minutes - exhaust widths ~ 2.4 x 105 km.

After J. Gosling

This is the largest exhaust yet identified in the solar wind and demonstrates prolonged reconnection at an extended and continuous X-line.

Gosling et al., GRL 2007

Reconnection event 31.08 – 1.09.2001

Normal coordinates LMN

Riemann problem for reconnection

B a

C

S

S

A

B b

B n

A

A

(R)

(R )

S-

S-

C

Heyn, Biernat, Rijnbeek, and Semenov, The Structure of Reconnection Layers,J. Plasma Phys., 1988.

Decay of discontinuity

BV

S-

B a

C

S

S

A

B b

A

S

C

S AExhaust

B a

B b

A

S

C

S

A

Exhaust

B a

B b

Structure of reconnection layer

3-D view 2-D projection

Alfven discontinuityAlfven discontinuity

Shock waveShock wave

)1(

,8

0}{

0}{

0))}((41

)21

({

0}41

{

0)}(81

{

0}{

2

22

222

p

BpP

ãäå

VBVB

B

VBBBVVV

BBVV

BBVP

V

nttn

n

nnn

tntn

ntn

n

01

01

00101

011

)||)(sgn(

||

pp

VVbmBVV

BbB

AAnA

)1)(1(1)(

4

)1)(1(21

1

))(||)(sgn(

||

2

1

2

2

0

2

01002

012

G

BP

ãäå

GVbVmBVV

BbB

a

a

AAn

)(||)(||||

))(sgn(

||1

))(||)(sgn(

))(||)(sgn(

||||

~

0

~

0

00

~

00

~

~

0

~

10

~~

0

0100

0

~~

0

GVGVh

VVVVmBnh

hh

b

GVbVmBV

GVbVmBV

BB

AA

AA

AAn

AAn

0

)(

nB

tVnVnR nSW

Sat1

Sat2

Sat3

WindACEGeotail

0 1 2 3 4 5 6-100

0

100

Vx

0 1 2 3 4 5 6-100

0

100

Vy

0 1 2 3 4 5 6-50

0

50

Vz

0 1 2 3 4 5 6-10

0

10

Bx

0 1 2 3 4 5 6-5

0

5

By

0 1 2 3 4 5 6-5

0

5

Bz

0 1 2 3 4 5 60

2

4

AS C S A

Reconnection event on 31 Aug – 1 Sep 2001 (WIND)

Reconnection event on 31 Aug – 1 Sep 2001 (GEOTAIL)

0 1 2 3 4 5 6-200

0

200Vx

0 1 2 3 4 5 6-100

0

100

Vy

0 1 2 3 4 5 6-50

0

50

Vz

0 1 2 3 4 5 6-5

0

5

Bx

0 1 2 3 4 5 6-5

0

5

By

0 1 2 3 4 5 6-5

0

5

Bz

0 1 2 3 4 5 60

1

2

AS C AS

Reconnection event on 31 Aug – 1 Sep 2001 (ACE)

0 1 2 3 4 5 6-50

0

50Vx

0 1 2 3 4 5 6-100

0

100

Vy

0 1 2 3 4 5 6-50

0

50

Vz

0 1 2 3 4 5 6-5

0

5

Bx

0 1 2 3 4 5 6-5

0

5

By

0 1 2 3 4 5 6-5

0

5

Bz

0 1 2 3 4 52

4

6

AS C AS

Interaction of solar wind with ICME

With reconnectionafter Erkaev N. V.

No reconnection after Erkaev N. V.

Pudovkin and Bogdanova, Geomag. Aeronomy, 2002

Interaction of solar wind with ICME

Reconnection in the solar wind:

Occurs at thin current sheets that separate distinctly different plasma states (tangential discontinuities).

Commonly is quasi-stationary and typically occurs at extended X-lines (~390 Re Phan et al. 2006, ~600 Re Gosling et al. 2007)

Produces Petschek-type exhausts of roughly Alfvenic jetting plasma bounded by rotational discontinuity-slow shock structure that bifurcate the original thin current sheet.

Slows down ICMEs with low magnetic shear and accelerates ICMEs with high shear.