Search Publications
Explanation for the Increase in High-Altitude Water on Mars Observed by NOMAD During the 2018 Global Dust Storm
Aoki, S.; Vandaele, A. C.; Daerden, F. +21 more
The Nadir and Occultation for MArs Discovery (NOMAD) instrument on board ExoMars Trace Gas Orbiter measured a large increase in water vapor at altitudes in the range of 40-100 km during the 2018 global dust storm on Mars. Using a three-dimensional general circulation model, we examine the mechanism responsible for the enhancement of water vapor in…
Global Model of Whistler Mode Chorus in the Near-Equatorial Region (|λm|< 18°)
Shen, Xiao-Chen; Meredith, Nigel P.; Horne, Richard B. +2 more
We extend our database of whistler mode chorus, based on data from seven satellites, by including ∼3 years of data from Radiation Belt Storm Probes (RBSP)-A and RBSP-B and an additional ∼6 years of data from Time History of Events and Macroscale Interactions during Substorms (THEMIS)-A, THEMIS-D, and THEMIS-E. The new database allows us to probe t…
Flux Erosion of Magnetic Clouds by Reconnection With the Sun's Open Flux
Nandy, Dibyendu; Pal, Sanchita; Dash, Soumyaranjan
Magnetic clouds (MCs) are flux rope magnetic structures forming a subset of solar coronal mass ejections, which have significant space weather impacts. The geoeffectiveness of MCs depends on their properties, which evolve during their interplanetary passage. Based on an analysis of observations spanning two solar cycles, we establish that MCs inte…
Formation and Evolution of the Large-Scale Magnetic Fields in Venus' Ionosphere: Results From a Three Dimensional Global Multispecies MHD Model
Luhmann, Janet; Toth, Gabor; Nagy, Andrew +2 more
Large-scale magnetic fields have been observed in Venus' ionosphere by both the Pioneer Venus Orbiter (PVO) and Venus Express spacecraft. In this study, we examine the formation and evolution of the large-scale magnetic field in the Venus ionosphere using a sophisticated global multispecies Magnetohydrodynamics (MHD) model that has been developed …
Identifying Active Kelvin-Helmholtz Vortices on Saturn's Magnetopause Boundary
Delamere, P. A.; Johnson, J. R.; Burkholder, B. L. +1 more
For ∼2,000 Cassini magnetopause encounters, we analyse plasma and magnetic fields. The boundary can be unstable to the Kelvin-Helmholtz instability (KHI), which can drive large-scale flows identifiable in plasma measurements. Bulk flow reversed from the expected direction near the magnetopause can indicate vorticity associated with active KH, and …
Momentum and Pressure Balance of a Comet Ionosphere
Nilsson, H.; Goetz, C.; Richter, I. +3 more
We calculate the momentum flux and pressure of ions measured by the Ion Composition Analyzer (ICA) on the Rosetta mission at comet 67P/Churyumov-Gerasimenko. The total momentum flux stays roughly constant over the mission, but the contributions of different ion populations change depending on heliocentric distance. The magnetic pressure, calculate…
Electron Acceleration in a Magnetotail Reconnection Outflow Region Using Magnetospheric MultiScale Data
Khotyaintsev, Yuri V.; Graham, Daniel B.; Vaivads, Andris +3 more
We study Magnetospheric MultiScale observations in the outflow region of magnetotail reconnection. We estimate the power density converted via the three fundamental electron acceleration mechanisms: Fermi, betatron, and parallel electric fields. The dominant mechanism, both on average and the peak values, is Fermi acceleration with a peak power de…
Is Nightside Outflow Required to Induce Magnetospheric Sawtooth Oscillations
Zhang, Binzheng; Brambles, Oliver J.; Lotko, William +1 more
Ionospheric outflow plays an important role in the mass coupling between the ionosphere and the coupled solar wind-magnetosphere system. Previous modeling studies have shown that outflowing ionospheric ions may induce magnetospheric sawtooth oscillations through mass loading of the magnetotail, stretching the magnetic field lines, and reducing nig…
Singing Comet Waves in a Solar Wind Convective Electric Field Frame
Goetz, C.; Taylor, M. G. G. T.; Plaschke, F.
The cometary plasma environment at low gas production rates is dominated by highly compressional, large-amplitude magnetic field waves in the 10-100 mHz range. They are thought to be caused by an ion-Weibel instability due to a cross-field current, which is caused by the cometary ions that are accelerated along the solar wind convective electric f…
Low-Frequency Radio Observations of the "Quiet" Corona During the Descending Phase of Sunspot Cycle 24
Ramesh, R.; Kumari, A.; Kathiravan, C. +3 more
We carried out a statistical study of the "quiet" solar corona during the descending phase of the Sunspot Cycle 24 (i.e., January 2015 to May 2019) using data obtained with the Gauribidanur RAdioheliograPH (GRAPH) at 53 and 80 MHz simultaneously. Our results show that the equatorial (east-west) diameters of the solar corona at the above two freque…