Search Publications
Correlation properties of magnetosheath magnetic field fluctuations
Němeček, Z.; Gutynska, O.; Šafránková, J.
The magnetosheath is characterized by a variety of low-frequency fluctuations, but their features and sources are different. Taking advantage of multipoint magnetic field measurements of the Cluster spacecraft, we present a statistical study to reveal properties of waves. We compute cross-correlation coefficients of magnetic field strengths as mea…
Source region of the 18 November 2003 coronal mass ejection that led to the strongest magnetic storm of cycle 23
Srivastava, Nandita; Mathew, Shibu K.; Louis, Rohan E. +1 more
The superstorm of 20 November 2003 was associated with a high-speed coronal mass ejection (CME) which originated in the NOAA AR 10501 on 18 November. This coronal mass ejection had severe terrestrial consequences leading to a geomagnetic storm with Dst index of -472 nT, the strongest of the current solar cycle. In this paper, we attempt to underst…
Reformation of an oblique shock observed by Cluster
Lucek, E. A.; Schwartz, S. J.; Mazelle, C. +2 more
On 16 March 2005, the Cluster spacecraft crossed a shock almost at the transition between the quasi-perpendicular and quasi-parallel regimes ($\theta$Bn = 46°) preceded by an upstream low-frequency (≈0.02 Hz in the spacecraft frame) wave train observed for more than 10 mn. The wave semicycle nearest to the shock was found to grow in tim…
Reconstruction of two-dimensional coherent structures in ideal and resistive Hall MHD: The theory
Sonnerup, Bengt U. Ö.; Teh, Wai-Leong
We demonstrate that it is possible, in principle, to use data from a single spacecraft to produce reconstructions of two-dimensional, time-independent field and plasma structures in space, in circumstances where the Hall effect is important. Such reconstruction generates maps, in a limited region around the spacecraft path, of magnetic and electri…
Determining ion production rates near Saturn's extended neutral cloud from ion cyclotron wave amplitudes
Russell, C. T.; Tokar, R. L.; Omidi, N. +2 more
Recent Cassini observations of active venting of water molecules from Enceladus indicate that the moon is the primary source of Saturn's extended neutral cloud. Ionization of the neutrals through charge exchange creates a population of newborn ions with a velocity space distribution, which is highly unstable to the generation of electromagnetic io…
Quantitative forecasting of near-term solar activity and upper atmospheric density
Lean, J. L.; Picone, J. M.; Emmert, J. T.
Autoregressive algorithms are developed to forecast solar activity on timescales of 1 to 10 days and utilized to forecast upper atmospheric densities using the NRLMSIS density specification model. Quantitative assessment of solar activity observations and forecasts made over 27 years (from 1980 to 2006) indicates that the chromospheric Mg index is…
Hybrid simulations of magnetic reconnection initiated in the magnetosheath
Omidi, N.; Sibeck, D. G.; Phan, T.
Interaction of solar wind tangential discontinuities (TDs) with the bow shock may initiate reconnection in the magnetosheath. We employ 2.5-D electromagnetic, hybrid simulations that treat the ions kinetically via particle-in-cell methods and the electrons as a massless fluid to study this interaction. We present results from eight runs correspond…
Hybrid simulation of foreshock waves and ion spectra and their linkage to cusp energetic ions
Wang, X. Y.; Lin, Y.; Chang, S. -W.
A three-dimensional global hybrid simulation is carried out to investigate energetic ions and electromagnetic waves in the quasi-parallel (Q-$\parallel$) bow shock and cusp for a typical interplanetary magnetic field configuration during the cusp energetic particle events. The bow shock, magnetosheath, and dayside magnetosphere form by interaction…
A simulation study of particle energization observed by THEMIS spacecraft during a substorm
Bosqued, Jean-Michel; El-Alaoui, Mostafa; Zhou, Meng +6 more
Energetic ions with hundreds of keV energy are frequently observed in the near-Earth tail during magnetospheric substorms. We examined the sources and acceleration of ions during a magnetospheric substorm on 1 March 2008 by using Time History of Events and Macroscale Interactions during Substorms (THEMIS) and Cluster observations and numerical sim…
Convective bursty flows in the near-Earth magnetotail inside 13 RE
Dunlop, M. W.; Baumjohann, W.; Carr, C. +8 more
With the 4-s resolution data of the magnetometer and the ion plasma analyzer on Double Star TC-1 from June to November of each year during the period of 2004-2006, we statistically analyzed the occurrence rate of both convective and field-aligned bursty flows (FABFs). In the region -13 RE < X < -9 RE, |Y| < 10 R…