Recognizing Reconnection in the Solar Wind: Recognizing
Reconnection in the Solar Wind:
The Magnetopause Connection
J. T. Gosling
LASP/University of Colorado
Boulder Colorado
Boulder Colorado
C. T. Russell 70
C
T Russell 70th Birthday Celebration 9 May, 2013
Birthday Celebration 9 May 2013
Flux Transfer Events at the Magnetopause
Quasi‐Stationary Reconnection at Earth’s Magnetopause
Plasma Interpenetration and Time‐of‐Flight Effects During Reconnection at Magnetopause
Effects During Reconnection at Magnetopause
Reconnection at the Magnetopause Tends to be Suppressed when the Magnetosheath Beta is Large
Suppressed when the Magnetosheath Beta is Large
Scurry et al
al. 1994
Some Suggested Solar Wind Reconnection Sites
Heliospheric Current Sheet
Parker [1983]: “Magnetic reconnection occurs to some degree throughout the solar wind …”
Leading Edge of ICMEs
Turbulence‐Generated Current Sheets
Matthaeus et al. [2003]: “…most of the energy in a nearly incompressible MHD cascade is expected to dissipate through small scale reconnection processes.”
ACE
The Context for the First Reconnection Exhaust Identified in the Solar Wind 272 eV electron pitch angle 272
V l t
it h
l
distribution
Np (cm‐33)
Tp (˚K)
Vp (km/s)
(k / )
Nα / Np (%)
B (nT)
Br (nT)
Bt (nT)
Bn (nT)
The First Solar Wind Reconnection Exhaust Identified
Field Shear Angle = 149˚
g
ACE
Np
Br
Vp
Vr
Tp
B t
Vt
Bn
Vn
T|| / T⊥
B
β
VA
Interpenetrating Proton Beams Within Reconnection Exhausts
Protons in Plasma Rest Frame
Protons in Plasma Rest Frame
Before
Exhaust
Exhaust
After
11/23/1997
2D projection
A Very Narrow Reconnection Exhaust
3‐s resolution data
92‐ms resolution data
Bt
Br
Bn
BN
BL
BM
Field shear angle: 62˚
A Reconnection Event at a Current Sheet Associated with a Very Small Field Shear Angle
Field Shear Angle = 15˚
Field Shear Angle = 15
3‐s plasma data
92‐ms magnetic field data
Reconnection is Pervasive in the Solar Wind
The Magnetic Shear Angle – Δβ Effect
Phan et al. 2010
Phan et al. 2010
Phan et al. 2010
L: width of density gradient across the
gradient across the current sheet
λi: ion skin depth
Reconnection is suppressed at small field shear
Reconnection
is suppressed at small field shear angles when Δβ
angles when Δβ is large is large
owing to diamagnetic drift of X‐line (Swisdak and Drake).
Multiple Spacecraft Observations of Reconnection Jets in the Solar Wind
2 February 2002
Ch i
Chris
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Connections i
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Reconnection and Asymmetric Polar y
Cap Convection
Reconnection at the Lobe Magnetopause
Lobe Magnetopause