Transmission of Solar Wind Hydromagnetic Energy Into the High Latitude Magnetosphere

1989 ◽  
pp. 203-209 ◽  
Author(s):  
A. Wolfe ◽  
L. J. Lanzerotti ◽  
C. G. Maclennan ◽  
R. Slawinski ◽  
D. Venkatesan
Keyword(s):  
Solar Wind ◽  
High Latitude

Relation of solar wind parameters to high-latitude magnetic pulsations

2006 ◽  
Vol 12 (1) ◽  
pp. 80-84
Author(s):  
S.N. Samsonov ◽  
◽  
I.Ya. Plotnikov ◽  
D.Y. Sibeck ◽  
Yu. Watermann ◽  
...  
Keyword(s):  
Solar Wind ◽  
High Latitude ◽  
Magnetic Pulsations ◽  
Solar Wind Parameters

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.

High-latitude observations of solar wind streams and coronal holes

1976 ◽  
Vol 81 (22) ◽  
pp. 3845-3850 ◽  
Author(s):  
B. J. Rickett ◽  
D. G. Sime ◽  
N. R. Sheeley ◽  
W. R. Crockett ◽  
R. Tousey
Keyword(s):  
Solar Wind ◽  
High Latitude ◽  
Coronal Holes

scholarly journals Detailed dayside auroral morphology as a function of local time for southeast IMF orientation: implications for solar wind-magnetosphere coupling

2004 ◽  
Vol 22 (10) ◽  
pp. 3537-3560 ◽  
Author(s):  
P. E. Sandholt ◽  
C. J. Farrugia ◽  
W. F. Denig
Keyword(s):  
Solar Wind ◽  
Local Time ◽  
High Latitude ◽  
Specific Activity ◽  
Moderate Intensity ◽  
Auroral Activity ◽  
Activity Intensity ◽  
Subsolar Point ◽  
Field Lines ◽  
Ground Magnetic

Abstract. In two case studies we elaborate on spatial and temporal structures of the dayside aurora within 08:00-16:00 magnetic local time (MLT) and discuss the relationship of this structure to solar wind-magnetosphere interconnection topology and the different stages of evolution of open field lines in the Dungey convection cycle. The detailed 2-D auroral morphology is obtained from continuous ground observations at Ny Ålesund (76° magnetic latitude (MLAT)), Svalbard during two days when the interplanetary magnetic field (IMF) is directed southeast (By>0; Bz<0). The auroral activity consists of the successive activations of the following forms: (i) latitudinally separated, sunward moving, arcs/bands of dayside boundary plasma sheet (BPS) origin, in the prenoon (08:00-11:00 MLT) and postnoon (12:00-16:00 MLT) sectors, within 70-75° MLAT, (ii) poleward moving auroral forms (PMAFs) emanating from the pre- and postnoon brightening events, and (iii) a specific activity appearing in the 07:00-10:00 MLT/75-80° MLAT during the prevailing IMF By>0 conditions. The pre- and postnoon activations are separated by a region of strongly attenuated auroral activity/intensity within the 11:00-12:00 MLT sector, often referred to as the midday gap aurora. The latter aurora is attributed to the presence of component reconnection at the subsolar magnetopause where the stagnant magnetosheath flow lead to field-aligned currents (FACs) which are of only moderate intensity. The much more active and intense aurorae in the prenoon (07:00-11:00 MLT) and postnoon (12:00-16:00 MLT) sectors originate in magnetopause reconnection events that are initiated well away from the subsolar point. The high-latitude auroral activity in the prenoon sector (feature iii) is found to be accompanied by a convection channel at the polar cap boundary. The associated ground magnetic deflection (DPY) is a Svalgaard-Mansurov effect. The convection channel is attributed to effective momentum transfer from the solar wind-magnetosphere dynamo in the high-latitude boundary layer (HBL), on the downstream side of the cusp.

Topology of currents in the high-latitude magnetosphere and magnetospheric response to variations in solar wind parameters

2009 ◽  
Vol 49 (8) ◽  
pp. 1172-1175
Author(s):  
E. E. Antonova ◽  
I. P. Kirpichev ◽  
I. L. Ovchinnikov ◽  
K. G. Orlova ◽  
S. S. Rossolenko
Keyword(s):  
Solar Wind ◽  
High Latitude ◽  
Solar Wind Parameters

Explicit IMF By-dependence in geomagnetic activity

2021 ◽  
Author(s):  
Lauri Holappa ◽  
Timo Asikainen ◽  
Kalevi Mursula
Keyword(s):  
Solar Wind ◽  
Geomagnetic Activity ◽  
Space Weather ◽  
High Latitude ◽  
Coupling Function ◽  
Future Space ◽  
Weather Modeling ◽  
Southern High Latitude ◽  
Imf Clock Angle ◽  
The Imf

&lt;p&gt;The interaction of the solar wind with the Earth&amp;#8217;s magnetic &amp;#64257;eld produces geomagnetic activity, which is critically dependent on the orientation of the interplanetary magnetic &amp;#64257;eld (IMF). Most solar wind coupling functions quantify this dependence on the IMF orientation with the so-called IMF clock angle in a way, which is symmetric with respect to the sign of the B&lt;sub&gt;y&lt;/sub&gt; component. However, recent studies have shown that IMF B&lt;sub&gt;y&lt;/sub&gt; is an additional, independent driver of high-latitude geomagnetic activity, leading to higher (weaker) geomagnetic activity in Northern Hemisphere (NH) winter for B&lt;sub&gt;y&lt;/sub&gt; &gt; 0 (B&lt;sub&gt;y&lt;/sub&gt; &lt; 0). For NH summer the dependence on the B&lt;sub&gt;y&lt;/sub&gt; sign is reversed. We quantify the size of this explicit B&lt;sub&gt;y&lt;/sub&gt;-e&amp;#64256;ect with respect to the solar wind coupling function, both for northern and southern high-latitude geomagnetic activity. We show that for a given value of solar wind coupling function, geomagnetic activity is about 40% stronger for B&lt;sub&gt;y&lt;/sub&gt; &gt; 0 than for B&lt;sub&gt;y&lt;/sub&gt; &lt; 0 in NH winter. We also discuss recent advances in the physical understanding of the B&lt;sub&gt;y&lt;/sub&gt;-effect. Our results highlight the importance of the IMF B&lt;sub&gt;y&lt;/sub&gt;-component for space weather and must be taken into account in future space weather modeling.&lt;/p&gt;

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