scholarly journals Characteristics of the magnetosheath electron boundary layer under northward interplanetary magnetic field: Implications for high-latitude reconnection

2005 ◽  
Vol 110 (A6) ◽  
Author(s):  
B. Lavraud
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Interplanetary Magnetic Field ◽  
High Latitude

scholarly journals Cluster multispacecraft observations at the high-latitude duskside magnetopause: implications for continuous and component magnetic reconnection

2005 ◽  
Vol 23 (2) ◽  
pp. 461-473 ◽  
Author(s):  
A. Retinò ◽  
M. B. Bavassano Cattaneo ◽  
M. F. Marcucci ◽  
A. Vaivads ◽  
M. André ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Magnetic Reconnection ◽  
Interplanetary Magnetic Field ◽  
Tangential Stress ◽  
High Latitude ◽  
Magnetic Shear ◽  
Magnetospheric Boundary ◽  
Flow Reversals ◽  
The Imf

Abstract. We report multispacecraft Cluster observations of magnetic reconnection at the high-latitude magnetopause/magnetospheric boundary layer (MP/BL) under mainly northward interplanetary magnetic field (IMF) conditions. The event we study is on 3 December 2001 when the Cluster spacecraft were skimming the high-latitude duskside MP/BL during a period of about four hours. The orbit and configuration of the spacecraft were such that at least one satellite was present in the MP/BL during most of that period. We present the evidence of reconnection in the form of tangential stress balance between the magnetosheath and the MP/BL (Walén test) and in several cases in the form of transmitted magnetosheath ions in the MP/BL and incident/reflected magnetosheath ions in the magnetosheath boundary layer (MSBL) . The observations are consistent with magnetic reconnection occurring tailward of the cusp and going on continuously for a period of about four hours. The observed directions of the reconnection flows are consistent with the IMF orientation, thus indicating that reconnection is globally controlled by the IMF. Observations of a few flow reversals suggest passages of the spacecraft close to the X-line. The observation of low magnetic shear across the magnetopause during a flow reversal is consistent with component merging at least in one case. The observation of reconnection flows on the duskside magnetopause irrespective of the change in the sign of the IMF BY also suggests a better agreement with the component merging model, though antiparallel merging cannot be excluded because the distance from the X-line is not known.

scholarly journals Interplanetary magnetic field control of Saturn's polar cusp aurora

2005 ◽  
Vol 23 (4) ◽  
pp. 1405-1431 ◽  
Author(s):  
E. J. Bunce ◽  
S. W. H. Cowley ◽  
S. E. Milan
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Interplanetary Magnetic Field ◽  
Field Line ◽  
High Latitude ◽  
Closed Field ◽  
Vortical Flows ◽  
Dayside Magnetopause ◽  
Closed Field Line ◽  
Lobe Reconnection

Abstract. Dayside UV emissions in Saturn's polar ionosphere have been suggested to be the first observational evidence of the kronian "cusp" (Gérard et al., 2004). The emission has two distinct states. The first is a bright arc-like feature located in the pre-noon sector, and the second is a more diffuse "spot" of aurora which lies poleward of the general location of the main auroral oval, which may be related to different upstream interplanetary magnetic field (IMF) orientations. Here we take up the suggestion that these emissions correspond to the cusp. However, direct precipitation of electrons in the cusp regions is not capable of producing significant UV aurora. We have therefore investigated the possibility that the observed UV emissions are associated with reconnection occurring at the dayside magnetopause, possibly pulsed, akin to flux transfer events seen at the Earth. We devise a conceptual model of pulsed reconnection at the low-latitude dayside magnetopause for the case of northwards IMF which will give rise to pulsed twin-vortical flows in the magnetosphere and ionosphere in the vicinity of the open-closed field-line boundary, and hence to bi-polar field-aligned currents centred in the vortical flows. During intervals of high-latitude lobe reconnection for southward IMF, we also expect to have pulsed twin-vortical flows and corresponding bi-polar field-aligned currents. The vortical flows in this case, however, are displaced poleward of the open-closed field line boundary, and are reversed in sense, such that the field-aligned currents are also reversed. For both cases of northward and southward IMF we have also for the first time included the effects associated with the IMF By effect. We also include the modulation introduced by the structured nature of the solar wind and IMF at Saturn's orbit by developing "slow" and "fast" flow models corresponding to intermediate and high strength IMF respectively. We then consider the conditions under which the plasma populations appropriate to either sub-solar reconnection or high-latitude lobe reconnection can carry the currents indicated. We have estimated the field-aligned voltages required, the resulting precipitating particle energy fluxes, and the consequent auroral output. Overall our model of pulsed reconnection under conditions of northwards and southwards IMF, and for varying orientations of IMF By, is found to produce a range of UV emission intensities and geometries which is in good agreement with the data presented by Gérard et al. (2004). The recent HST-Cassini solar wind campaign provides a unique opportunity to test the theoretical ideas presented here.

scholarly journals Northward interplanetary magnetic field cusp aurora and high-latitude magnetopause reconnection

1997 ◽  
Vol 102 (A6) ◽  
pp. 11349-11362 ◽  
Author(s):  
M. Øieroset ◽  
P. E. Sandholt ◽  
W. F. Denig ◽  
S. W. H. Cowley
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
High Latitude ◽  
Magnetopause Reconnection

scholarly journals Variability of Geomagnetic Field with Interplanetary Magnetic Field at Low, Mid and High Latitudes

2018 ◽  
Vol 10 (2) ◽  
pp. 133-144
Author(s):  
S. Bhardwaj ◽  
P. A. Khan ◽  
R. Atulkar ◽  
P. K. Purohit
Keyword(s):  
Magnetic Field ◽  
Coronal Mass Ejection ◽  
Interplanetary Magnetic Field ◽  
Geomagnetic Storm ◽  
High Latitude ◽  
Geomagnetic Field ◽  
The State ◽  
High Latitudes ◽  
Storm Events ◽  
Mass Ejection

 The fluctuations in the Interplanetary Magnetic Field significantly affect the state of geomagnetic field particularly during the Coronal Mass Ejection (CME) events. In the present investigation we have studied the influence of Interplanetary Magnetic Field changes on the geomagnetic field components at high, low and mid latitudes. To carry out this investigation we have selected three stations viz. Alibag (18.6°N, 72.7°E), Beijing MT (40.3°N, 116.2°E) and Casey (66.2°S, 110.5°E) one each in the low, mid and high latitude regions. Then we selected geomagnetic storm events of three types namely weak (-50≤Dst≤-20), moderate (100≤Dst≤-50) and intense (Dst≤-100nT). In each storm category 10 events were considered. From our study we conclude that geomagnetic field components are significantly affected by the changes in the IMF at all the three latitudinal regions during all the storm events. At the same time we also found that the magnitude of change in geomagnetic field components is highest at the high latitudes during all types of storm events while at low and mid latitude stations the magnitude of effect is approximately the same.

scholarly journals Effect of the interplanetary magnetic field Y component on the high-latitude nightside convection

1985 ◽  
Vol 12 (7) ◽  
pp. 461-464 ◽  
Author(s):  
O. de la Beaujardière ◽  
V. B. Wickwar ◽  
J. D. Kelly ◽  
J. H. King
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
High Latitude

Interplanetary magnetic field control of high-latitude activity on July 29, 1977

1982 ◽  
Vol 87 (A8) ◽  
pp. 5963 ◽  
Author(s):  
L. J. Zanetti ◽  
T. A. Potemra ◽  
J. P. Doering ◽  
J. S. Lee ◽  
J. F. Fennell ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
High Latitude ◽  
Field Control
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