Search Publications
Acceleration of radiation belts electrons by oblique chorus waves
Krasnoselskikh, V.; Agapitov, O.; Artemyev, A. +1 more
The redistribution of energy during the recovery phase of geomagnetic storms related to the acceleration of electrons in the Earth's outer radiation belt by cyclotron-resonant chorus waves is an important and challenging topic of magnetospheric plasma physics. An approximate analytical formulation of energy diffusion coefficients is derived in thi…
An MHD simulation model of time-dependent co-rotating solar wind
Hayashi, K.
We present a treatment of observation-based time-dependent boundary conditions for the inner boundary sphere in the time-dependent three-dimensional MHD simulations of the global solar wind. With this boundary treatment, we obtain super-Alfvenic MHD solutions of time-dependent co-rotating solar wind structures. The boundary variables on the inner …
A statistical study of the cross-shock electric potential at low Mach number, quasi-perpendicular bow shock crossings using Cluster data
Bale, S. D.; Walker, S. N.; Balikhin, M. A. +3 more
The cross-shock electrostatic potential at the front of collision-less shocks plays a key role in the distribution of energy at the shock front. Multipoint measurements such as those provided by the Cluster II mission provide an ideal framework for the study of the cross-shock potential because of their ability to distinguish between temporal and …
Dependence of solar proton events on their associated activities: Coronal mass ejection parameters
Moon, Y. -J.; Gopalswamy, N.; Park, J.
In this study we have examined the occurrence probability of solar proton events (SPEs) and their peak fluxes depending on coronal mass ejection (CME) parameters, linear speed (V), angular width (AW), and location (L). For this we used the NOAA SPE list and their associated CME data from 1997 to 2006. We found that the probability strongly depends…
Numerical simulation of the effects of a solar energetic particle event on the ionosphere of Mars
Simon Wedlund, C.; Haider, S. A.; Withers, Paul +5 more
We investigate the ionospheric effects of a solar energetic particle (SEP) event at Mars, specifically the 29 September 1989 event. We use its energy spectrum and a steady state ionospheric model to simulate vertical profiles of ion and electron densities. The ionospheric response to this large event would have been readily observable. It caused e…
Impact of the rippling of a perpendicular shock front on ion dynamics
Lembège, B.; Lu, Q. M.; Yang, Z. W.
Both hybrid/full particle simulations and recent experimental results have clearly evidenced that the front of a supercritical quasi-perpendicular shock can be rippled. Recent two-dimensional simulations have focused on two different types of shock front rippling: (1) one characterized by a small spatial scale along the front is supported by lower…
A statistical comparison of solar wind propagation delays derived from multispacecraft techniques
Wild, J. A.; Case, N. A.
We present a large-scale statistical study of the solar wind propagation delay between NASA's Advanced Composition Explorer spacecraft and ESA's Cluster 1 spacecraft. This study focuses on those periods when Cluster was within the unimpeded solar wind, upstream of the bow shock nose, between 2001 and 2010. Using a cross-correlation method to compa…
Spatial gradients from irregular, multiple-point spacecraft configurations
Dunlop, M. W.; Rème, H.; Liu, Z. X. +8 more
We present a generalized multipoint analysis of physical quantities, such as magnetic field and plasma flow, based on spatial gradient properties, where the multipoint data may be taken by irregular (distorted) configurations of any number of spacecraft. The methodology is modified from a previous, fully 3-D gradient analysis technique, designed t…
Transport of thermal-energy ionospheric oxygen (O+) ions between the ionosphere and the plasma sheet and ring current at quiet times preceding magnetic storms
Peterson, W. K.; Yau, Andrew W.; Abe, Takumi +1 more
The presence of energetic O+ ions in the ring current at the onset of a magnetic storm prompts the question of the possible role of “in-transit” ionospheric O+ ions between the ionosphere and the plasma sheet and ring current in the quiet periods immediately preceding the main phase of a magnetic storm. Thermal-energy O+…
Nonlinear interaction between ring current protons and electromagnetic ion cyclotron waves
Zhu, Hui; Su, Zhenpeng; Xiao, Fuliang +4 more
Electromagnetic ion cyclotron (EMIC) waves have long been suggested to account for the rapid decay of ring current, which is usually described by the quasi-linear theory. We demonstrate that the interactions between ring current protons and typical EMIC waves can be highly nonlinear. A dimensionless parameterRis derived to identify the nonlinear i…