Magnetosphere Seminars

2016 - Spring Schedule

Mar 22, 2016 – Propagation and Nonlinear Amplification of Whistler Mode Waves in the Earth’s Magnetosphere

Speaker:   Mark Golkowski (CU Denver)
Date & Time:   Mar 22, 2016 ,  4:00 PM Location: LASP Space Science Building, room N100 (first floor)
Abstract:  

Whistler mode waves are known to be a key driver in magnetospheric dynamics.  The propagation trajectories of whistler mode waves are traditionally calculated using a cold plasma approximation.  We show that at frequencies near the lower hybrid resonance, the effect of ambient ~1eV electron and ion temperatures can have significant effect on the propagation trajectories. … Read more »

Mar 29, 2016 – Interplanetary Shocks

Speaker:   Lynn Wilson (NASA GSFC)
Date & Time:   Mar 29, 2016 ,  4:00 PM Location: LASP Space Science Building, room N100 (first floor)
Abstract:  

What is the relative importance of small-scale, microphysical plasma processes to those occurring on macroscopic scales?  This is a fundamental and unresolved question in plasma and astrophysical research.  In my talk, I will highlight some of our recent work [Wilson et al., 2014a,b] showing that wave-particle interactions, on small-scales (10’s of meters), can produce enough… Read more »

Feb 2, 2016 – The ‘Zebra Stripes’: An Imprint of Ionospheric Winds on Radiation Belts

Speaker:   Solene Lejosne (UC Berkeley)
Date & Time:   Feb 2, 2016 ,  4:00 PM Location: LASP Space Science Building, room N100 (first floor)
Abstract:  

We examine a characteristic effect, namely the ubiquitous appearance of structured peaks and valleys called zebra stripes in the spectrograms of energetic electrons and ions trapped in the inner belt below L~3. We propose an explanation of this phenomenon as a purely kinematic consequence of particle drift velocity modulation caused by F-region zonal plasma drifts… Read more »

Feb 16, 2016 – Electric fields in the inner magnetosphere and deep injections of 100s keV electrons

Speaker:   Sam Califf (LASP/CU)
Date & Time:   Feb 16, 2016 ,  4:00 PM Location: LASP Space Science Building, room N100 (first floor)
Abstract:  

This talk focuses on in situ electric field observations in the inner magnetosphere and their relation to energetic electron dynamics, specifically at the inner edge of the outer radiation belt.  We begin with a description of the double-probe technique for measuring electric fields, followed by characteristics of the large-scale electric field based on many years… Read more »

Feb 23, 2016 – International Magnetospheric Collaboration during the Cold War

Speaker:   Juan Roederer (UAF)
Date & Time:   Feb 23, 2016 ,  4:00 PM Location: LASP Space Science Building, room N100 (first floor)
Abstract:  

The term “magnetosphere” was invented by British Physicist Tommy Gold of Cornell University, who in 1959 used it to designate the magnetized plasma environment of Earth—just a few years after the International Geophysical Year (IGY) and the discovery of the radiation belts by Sergei Vernov and James Van Allen (in that temporal order—unfortunately for Vernov,… Read more »

Mar 1, 2016 – Ion Acceleration at Injection Fronts in the Inner Magnetosphere

Speaker:   Sasha Ukhorskiy (JHUAPL)
Date & Time:   Mar 1, 2016 ,  4:00 PM Location: LASP Space Science Building, room N100 (first floor)
Abstract:  

During geomagnetic storms a large volume of ions are transported from the magnetotail deep into the inner magnetosphere leading to ion acceleration to the energies of tens to hundreds keV. Energized ions become the dominant source of plasma pressure in the inner magnetosphere. Hot plasma pressure drives large electrical currents which determine global electrodynamics and… Read more »

Mar 8, 2016 – What have we learned about the inner belt from the Van Allen Probes and CSSWE missions?

Speaker:   Xinlin Li (LASP/CU)
Date & Time:   Mar 8, 2016 ,  4:00 PM Location: LASP Space Science Building, room N100 (first floor)
Abstract:  

Comprehensive measurements of the inner belt protons from the Relativistic Electron and Proton Telescope (REPT) onboard Van Allen Probes, in a geo-transfer-like orbit, revealed new features of inner belt protons in terms of their spectrum distribution, spatial distribution, pitch angle distribution, and their different source populations. Concurrent measurements from the Relativistic Electron and Proton Telescope… Read more »

Mar 29, 2016 – Energy dissipation at the terrestrial bow shock

Speaker:   Lynn Wilson (NASA Goddard Space Flight Center)
Date & Time:   Mar 29, 2016 ,  4:00 PM Location: LASP Space Science Building, room N100 (first floor)
Abstract:  

What is the relative importance of small-scale, microphysical plasma processes to those occurring on macroscopic scales?  This is a fundamental and unresolved question in plasma and astrophysical research.  In my talk, I will highlight some of our recent work [Wilson et al., 2014a,b] showing that wave-particle interactions, on small-scales (10’s of meters), can produce enough… Read more »

May 10, 2016 – The role of radial transport in rebuilding the Earth’s outer electron belts

Speaker:   Brian Kress (NOAA)
Date & Time:   May 10, 2016 ,  4:00 PM Location: LASP Space Science Building, room N100 (first floor)
Abstract:  

The build up of ~1 MeV electrons near geosynchronous during strong geomagnetic storms is mainly due to enhanced global convection and dipolarization associated injections from the plasma sheet. Van Allen Probes energetic particle measurements show injection of electrons with energies up to 2 MeV well inside of geosynchronous, however, it remains unknown to what extent… Read more »

Jul 19, 2016 – Rippled quasi-perpendicular shock observed by MMS

Speaker:   Andreas Johlander (IRFU, Sweden)
Date & Time:   Jul 19, 2016 ,  4:00 PM Location: LASP Space Science Building, room N100 (1st floor)
Abstract:  

Collisionless shock non-stationarity arising from micro-scale physics influences shock structure and particle acceleration mechanisms. Non-stationarity has been difficult to quantify due to the small spatial and temporal scales. We use the closely-spaced (sub-gyroscale), high time-resolution measurements from one rapid quasi-perpendicular shock crossing by the Magnetospheric Multiscale (MMS) spacecraft to compare competing non-stationarity processes. Using MMS’s… Read more »