Search Publications
Prediction and understanding of the north-south displacement of the heliospheric current sheet
Hoeksema, J. T.; Scherrer, P. H.; Zhao, X. P.
On the basis of Wilcox Solar Observatory observations of the photospheric magnetic field and the potential field-source surface model, we compare the solid angles occupied by the positive source surface field with that of the negative. We develop an algorithm to quantitatively estimate and understand the positive-negative displacement of the helio…
Orientation and motion of two-dimensional structures in a space plasma
Hasegawa, H.; Sonnerup, B. U. Ã. -.
We present a new least squares technique for the determination of axis orientation, motion, and intrinsic axial electric field for two-dimensional coherent structures in a space plasma. This single-spacecraft method is based on Faraday's law, which, under the model assumptions, requires the intrinsic axial electric field to be constant in space an…
Computing the reconnection rate at the Earth's magnetopause using two spacecraft observations
RèMe, H.; Owen, C. J.; Fuselier, S. A. +2 more
A new multispacecraft technique is introduced which, under some restrictive assumptions and conditions, provides a snapshot of the reconnection inflow velocity into the magnetosphere and an estimate of the distance from the spacecraft to the reconnection site. The two quantities are not obtained independent of one another and additional, independe…
Examination of type II origin with SOHO/LASCO observations
Cho, K. -S.; Kim, Y. -H.; Moon, Y. -J. +5 more
We examine a possibility that metric type II solar radio bursts are all caused by coronal mass ejection (CME) generated shocks. For this we consider 129 type II flare events from February 1997 to October 2000 and examine their associations with SOHO/LASCO CMEs according to their temporal and spatial closeness using SOHO/EIT and GOES data. We then …
Nonlinear decay of foreshock Langmuir waves in the presence of plasma inhomogeneities: Theory and Cluster observations
Krasnoselskikh, V.; Dudok de Wit, T.; Soucek, J. +2 more
The intense high-frequency electrostatic waves observed in the terrestrial foreshock often have a form of a superposition of two monochromatic waves close to the plasma frequency. We suggest an interpretation of these spectra as signatures of nonlinear decay of Langmuir waves to electron-sound and ion-sound secondary waves. This decay instability …
October/November 2003 interplanetary coronal mass ejections: ACE/EPAM solar energetic particle observations
Lario, D.; Lanzerotti, L. J.; Sarris, E. T. +3 more
In late October and early November 2003 the ACE spacecraft at 1 AU detected two shock-associated interplanetary coronal mass ejections (ICMEs). In the sheath region formed in front of both ICMEs, some of the highest speeds ever directly measured in the solar wind were observed. We analyze in detail the energetic particle signatures measured at 1 A…
Solar wind from the coronal hole boundaries
Geiss, J.; McComas, D. J.; Schwadron, N. A. +3 more
Recent studies using in situ observations established that the interface between fast and slow wind in interplanetary space has two distinct parts: a smoothly varying boundary layer flow that flanks fast wind from coronal holes and a sharper plasma discontinuity between intermediate and slow solar wind. Other studies using in situ observations and…
Dynamic Harris current sheet thickness from Cluster current density and plasma measurements
Balogh, A.; Khurana, K. K.; Kistler, L. M. +5 more
We use the first accurate measurements of current densities in the plasma sheet to calculate the half-thickness and position of the current sheet as a function of time. Our technique assumes a Harris current sheet model, which is parameterized by lobe magnetic field B0, current sheet half-thickness h, and current sheet position z0<…
Interplanetary conditions and magnetospheric dynamics during the Cassini orbit insertion fly-through of Saturn's magnetosphere
Jackman, C. M.; Kurth, W. S.; Cecconi, B. +5 more
The primary purpose of this paper is to discuss the interplanetary conditions that prevailed during the Saturn orbit insertion (SOI) fly-through of Saturn's magnetosphere by the Cassini spacecraft in June-July 2004 and the consequent magnetospheric dynamics. We begin by examining concurrent interplanetary magnetic field (IMF) and Saturn kilometric…
On the generation of enhanced sunward convection and transpolar aurora in the high-latitude ionosphere by magnetic merging
Balogh, A.; RèMe, H.; Dunlop, M. W. +11 more
The IMAGE Wideband Imaging Camera (WIC) instrument observed the duskside development of an oval-aligned transpolar auroral arc (TPA) in the Northern Hemisphere (NH) on 16 December 2001 during strong IMF ∣B∣ ∼ 18 nT and a generally steady ∼56° clock angle (positive IMF By and Bz). Observational evidence suggests that the daysi…