Search Publications
Small-Scale Flux Transfer Events Formed in the Reconnection Exhaust Region Between Two X Lines
Russell, C. T.; Eastwood, J. P.; Lavraud, B. +18 more
We report MMS observations of the ion-scale flux transfer events (FTEs) that may involve two main X lines and tearing instability between the two X lines. The four spacecraft detected multiple isolated regions with enhanced magnetic field strength and bipolar Bn signatures normal to the nominal magnetopause, indicating FTEs. The current…
Field-Aligned Currents in Saturn's Nightside Magnetosphere: Subcorotation and Planetary Period Oscillation Components During Northern Spring
Dougherty, M. K.; Alexeev, I. I.; Belenkaya, E. S. +7 more
We newly analyze Cassini magnetic field data from the 2012/2013 Saturn northern spring interval of highly inclined orbits and compare them with similar data from late southern summer in 2008, thus providing unique information on the seasonality of the currents that couple momentum between Saturn's ionosphere and magnetosphere. Inferred meridional …
Dependence of Generation of Whistler Mode Chorus Emissions on the Temperature Anisotropy and Density of Energetic Electrons in the Earth's Inner Magnetosphere
Miyake, Y.; Usui, H.; Nakashima, H. +2 more
We carry out a series of self-consistent electron hybrid code simulations for the dependence of chorus generation process on the temperature anisotropy and density of energetic electrons in the Earth's inner magnetosphere. We use the same magnetic field gradient in the simulation system and different temperature anisotropy AT for the in…
Hubble Space Telescope Observations of Variations in Ganymede's Oxygen Atmosphere and Aurora
Milan, S. E.; Nichols, J. D.; Clarke, J. T. +7 more
We present high-sensitivity Hubble Space Telescope (HST) Cosmic Origins Spectrograph and HST Space Telescope Imaging Spectrograph measurements of atmospheric OI 130.4-nm and OI] 135.6-nm emissions at Ganymede, which exhibit significant spatial and temporal variability. These observations represent the first observations of Ganymede using HST Cosmi…
On the Existence of Ionospheric Feedback Instability in the Earth's Magnetosphere-Ionosphere System
Mishin, Evgeny V.; Streltsov, Anatoly V.
The ionospheric feedback instability (IFI) has been considered one of the main generation mechanisms for large-amplitude ultralow frequency waves and small-scale field-aligned currents in the auroral and subauroral regions for more than 40 years. Sydorenko and Rankin (2017, https://doi.org/10.1002/201…
The Distribution of Two Flapping Types of Magnetotail Current Sheet: Implication for the Flapping Mechanism
Petrukovich, A. A.; Wei, Y.; Dunlop, M. W. +6 more
Flapping motion of the current sheets of planetary magnetotails is a common dynamic phenomenon. Previous studies of the Earth's magnetotail suggest that its flapping motion has two forms, that is, kink-like flapping that can propagate as waves toward both flanks and steady flapping that moves up and down but does not propagate. Although some model…
Shapes of Magnetically Controlled Electron Density Structures in the Dayside Martian Ionosphere
Wild, J. A.; Kopf, A. J.; Diéval, C.
Nonhorizontal localized electron density structures associated with regions of near-radial crustal magnetic fields are routinely detected via radar oblique echoes on the dayside of Mars with the ionospheric sounding mode of the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) radar onboard Mars Express. Previous studies mostly …
Field-Aligned Currents in Saturn's Magnetosphere: Observations From the F-Ring Orbits
Dougherty, M. K.; Cowley, S. W. H.; Bunce, E. J. +3 more
We investigate the azimuthal magnetic field signatures associated with high-latitude field-aligned currents observed during Cassini's F-ring orbits (October 2016-April 2017). The overall ionospheric meridional current profiles in the northern and southern hemispheres, that is, the regions poleward and equatorward of the field-aligned currents, dif…
Multispacecraft Observations of Tailward Propagation of Transient Foreshock Perturbations to Midtail Magnetosheath
Wang, Chih-Ping; Liu, Terry Z.; Masson, Arnaud +1 more
We present three events from multiple spacecraft observations to show that a dayside transient foreshock perturbation associated with an interplanetary magnetic field directional discontinuity can propagate in the midtail magnetosheath and affect the magnetopause. In the first event, perturbations in density and flow were first observed in the day…
Recurrent Magnetic Dipolarization at Saturn: Revealed by Cassini
Coates, A. J.; Krupp, N.; Dougherty, M. K. +17 more
Planetary magnetospheres receive plasma and energy from the Sun or moons of planets and consequently stretch magnetic field lines. The process may last for varied timescales at different planets. From time to time, energy is rapidly released in the magnetosphere and subsequently precipitated into the ionosphere and upper atmosphere. Usually, this …