Search Publications
Solar and interplanetary sources of major geomagnetic storms (Dst <= -100 nT) during 1996-2005
Thompson, B. J.; Webb, D. F.; Zhukov, A. N. +9 more
We present the results of an investigation of the sequence of events from the Sun to the Earth that ultimately led to the 88 major geomagnetic storms (defined by minimum Dst ≤ -100 nT) that occurred during 1996-2005. The results are achieved through cooperative efforts that originated at the Living with a Star (LWS) Coordinated Data-Analysis Works…
Geoeffectiveness of halo coronal mass ejections
Gopalswamy, N.; Yashiro, S.; Akiyama, S.
We studied the geoeffectiveness, speed, solar source, and flare association of a set of 378 halo coronal mass ejections (CMEs) of cycle 23 (1996-2005, inclusive). We compiled the minimum Dst values occurring within 1-5 days after the CME onset. We compared the distributions of such Dst values for the following subsets of halo CMEs: disk halos (wit…
Magnetospheric configurations from a high-resolution data-based magnetic field model
Sitnov, M. I.; Tsyganenko, N. A.
We present first results of the magnetospheric magnetic field modeling, based on large sets of spacecraft data and a high-resolution expansion for the field of equatorial currents. In this approach, the field is expanded into a sum of orthogonal basis functions of different scales, capable to reproduce arbitrary radial and azimuthal variations of …
Energetic electron acceleration in the downstream reconnection outflow region
Balogh, A.; RèMe, H.; Daly, P. W. +5 more
Energetic electrons in an earthward reconnection outflow region have been observed by Cluster/Research with Adaptive Particle Imaging Detectors. We found a good correlation between the energetic electron enhancement and a normal magnetic field (Bz) enhancement within a 0.25-s time resolution. The large normal magnetic field is thought t…
Multi-point observations of the Hall electromagnetic field and secondary island formation during magnetic reconnection
Balogh, A.; Dandouras, I.; Eastwood, J. P. +7 more
A key feature of collisionless magnetic reconnection is the formation of Hall magnetic and electric field structure in the vicinity of the diffusion region. Here we present multi-point Cluster observations of a reconnection event in the near-Earth magnetotail where the diffusion region was nested by the Cluster spacecraft; we compare observations …
Saturnian magnetospheric dynamics: Elucidation of a camshaft model
Southwood, D. J.; Kivelson, M. G.
Periodic modulation of magnetospheric phenomena at Earth and Jupiter results principally from the tilt of the dipole axis relative to the rotation axis. Saturn's nearly aligned dipole moment is tilted by less than 0.5° from the spin axis, yet the power of radio-frequency emissions, the orientation of the magnetic field, and many properties of the …
Cassini observations of the variation of Saturn's ring current parameters with system size
Russell, C. T.; Dougherty, M. K.; Alexeev, I. I. +4 more
We have examined residual magnetic field vectors observed in Saturn's magnetosphere during the first 2 years of the Cassini mission and have fit them to a simple axisymmetric model of the ring current in the middle magnetosphere. We then examine the variations of the ring current parameters with size of the magnetosphere. In addition, we obtain se…
V arc interplanetary coronal mass ejections observed with the Solar Mass Ejection Imager
Webb, D. F.; Kahler, S. W.
Since February 2003, the Solar Mass Ejection Imager (SMEI) has been observing interplanetary coronal mass ejections (ICMEs) at solar elongation angles $\epsilon$ > 20°. The ICMEs generally appear as loops or arcs in the sky, but five show distinct outward concave shapes that we call V arcs. We expect to observe some V arcs, formed by trailing e…
Cluster observations of waves in the whistler frequency range associated with magnetic reconnection in the Earth's magnetotail
Dandouras, I.; Lucek, E.; RèMe, H. +7 more
On 21 August 2002 the Cluster spacecraft encountered a quasi-collisionless magnetic reconnection event when it crossed the plasma sheet. Prior to the southward turning of magnetic field in the tailward flow, the weak whistler waves were first observed. The burst of whistler waves appeared about 30 s earlier than the southward turning. During magne…
Cassini Ion and Neutral Mass Spectrometer data in Titan's upper atmosphere and exosphere: Observation of a suprathermal corona
Luhmann, J. G.; Johnson, R. E.; Leblanc, F. +10 more
The neutral nitrogen and methane measurements made by Ion and Neutral Mass Spectrometer during Cassini flybys TA, TB, and T5 in Titan's upper atmosphere and exosphere are presented. Large horizontal variations are observed in the total density, recorded to be twice as large during TA as during T5