Search Publications
Suprathermal particle energization in dipolarization fronts: Particle-in-cell simulations
Angelopoulos, V.; Fu, Huishan; Lu, San
Within dipolarization fronts (DFs) in the Earth's magnetotail, significant magnetic energy is converted to plasma energy, and a significant portion of the electrons and ions therein are accelerated to suprathermal energies. The mechanism that produces these suprathermal particles while simultaneously reducing magnetic field energy is poorly unders…
Identifying magnetic reconnection events using the FOTE method
Vaivads, A.; Cao, J. B.; Dunlop, M. +8 more
A magnetic reconnection event detected by Cluster is analyzed using three methods: Single-spacecraft Inference based on Flow-reversal Sequence (SIFS), Multispacecraft Inference based on Timing a Structure (MITS), and the First-Order Taylor Expansion (FOTE). Using the SIFS method, we find that the reconnection structure is an X line; while using th…
The plasma structure of coronal hole solar wind: Origins and evolution
Borovsky, Joseph E.
Whereas slow solar wind is known to be highly structured, the fast (coronal hole origin) wind is usually considered to be homogeneous. Using measurements from Helios 1 + 2, ACE, Wind, and Ulysses, structure in the coronal hole origin solar wind is examined from 0.3 AU to 2.3 AU. Care is taken to collect and analyze intervals of "unperturbed corona…
A model for stealth coronal mass ejections
Luhmann, J. G.; Li, Y.; Masson, S. +4 more
Stealth coronal mass ejections (CMEs) are events in which there are almost no observable signatures of the CME eruption in the low corona but often a well-resolved slow flux rope CME observed in the coronagraph data. We present results from a three-dimensional numerical magnetohydrodynamics (MHD) simulation of the 1-2 June 2008 slow streamer blowo…
Predicting the amplitude and hemispheric asymmetry of solar cycle 25 with surface flux transport
Hathaway, David H.; Upton, Lisa A.
Evidence strongly indicates that the strength of the Sun's polar fields near the time of a sunspot cycle minimum determines the strength of the following solar activity cycle. We use our Advective Flux Transport code, with flows well constrained by observations, to simulate the evolution of the Sun's polar magnetic fields from early 2016 to the en…
Characterizing cometary electrons with kappa distributions
Frahm, R. A.; Eriksson, A.; Henri, P. +17 more
The Rosetta spacecraft has escorted comet 67P/Churyumov-Gerasimenko since 6 August 2014 and has offered an unprecedented opportunity to study plasma physics in the coma. We have used this opportunity to make the first characterization of cometary electrons with kappa distributions. Two three-dimensional kappa functions were fit to the observations…
Whistler emission in the separatrix regions of asymmetric magnetic reconnection
André, M.; Vaivads, A.; Khotyaintsev, Yu. V. +1 more
At Earth's dayside magnetopause asymmetric magnetic reconnection occurs between the cold dense magnetosheath plasma and the hot tenuous magnetospheric plasma, which differs significantly from symmetric reconnection. During magnetic reconnection the separatrix regions are potentially unstable to a variety of instabilities. In this paper observation…
Two types of whistler waves in the hall reconnection region
Vaivads, A.; Retino, A.; Sahraoui, F. +13 more
Whistler waves are believed to play an important role during magnetic reconnection. Here we report the near-simultaneous occurrence of two types of the whistler-mode waves in the magnetotail Hall reconnection region. The first type is observed in the magnetic pileup region of downstream and propagates away to downstream along the field lines and i…
Europa's far ultraviolet oxygen aurora from a comprehensive set of HST observations
Saur, Joachim; Roth, Lorenz; Feldman, Paul D. +6 more
We analyze a large set of far ultraviolet oxygen aurora images of Europa's atmosphere taken by Hubble's Space Telescope Imaging Spectrograph (HST/STIS) in 1999 and on 19 occasions between 2012 and 2015. We find that both brightness and aurora morphology undergo systematic variations correlated to the periodically changing plasma environment. The t…
The inner magnetosphere ion composition and local time distribution over a solar cycle
Kistler, L. M.; Mouikis, C. G.
Using the Cluster/Composition and Distribution Function (CODIF) analyzer data set from 2001 to 2013, a full solar cycle, we determine the ion distributions for H+, He+, and O+ in the inner magnetosphere (L < 12) over the energy range 40 eV to 40 keV as a function magnetic local time, solar EUV (F10.7)…