A5027225617- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Astro and Planetary Science
- Spacecraft Design and Technology
- Characterization and Applications of Magnetic Nanoparticles
- Magnetic confinement fusion research
- Spacecraft and Cryogenic Technologies
- Geophysical and Geoelectrical Methods
- Space Satellite Systems and Control
- Geological and Geochemical Analysis
- Atmospheric Ozone and Climate
- Earthquake Detection and Analysis
- Reflective Practices in Education
- Power Transformer Diagnostics and Insulation
- Magnetic Properties and Applications
- Stellar, planetary, and galactic studies
- Inertial Sensor and Navigation
- Particle accelerators and beam dynamics
- Teaching and Learning Programming
- Minerals Flotation and Separation Techniques
- earthquake and tectonic studies
- Methane Hydrates and Related Phenomena
- Radio Astronomy Observations and Technology
- Water Quality Monitoring and Analysis
University of Colorado Boulder
2013-2018
Laboratory for Atmospheric and Space Physics
2013-2018
Haverford College
2013
Abstract The four Magnetospheric Multiscale (MMS) spacecraft recorded the first direct evidence of reconnection exhausts associated with Kelvin‐Helmholtz (KH) waves at duskside magnetopause on 8 September 2015 which allows for local mass and energy transport across flank magnetopause. Pressure anisotropy‐weighted Walén analyses confirmed in‐plane 22 42 KH‐related trailing current sheets (CSs). Twenty‐one jets were observed by all spacecraft, small variations in ion velocity, along same...
Abstract Spatial and high‐time‐resolution properties of the velocities, magnetic field, 3‐D electric field within plasma turbulence are examined observationally using data from Magnetospheric Multiscale mission. Observations a Kelvin‐Helmholtz instability (KHI) on Earth's magnetopause examined, which both provides series repeatable intervals to analyze, giving better statistics, first look at in KHI. For time direct observations high‐frequency ion electron velocity spectra showing differing...
We report observations from the Magnetospheric Multiscale (MMS) satellites of a large guide field magnetic reconnection event. The suggest that two four MMS spacecraft sampled electron diffusion region, whereas other detected exhaust jet amplitude is approximately 4 times reconnecting field. event accompanied by significant parallel electric (E_{∥}) larger than predicted simulations. high-speed (∼300 km/s) crossing region limited data set to one complete distribution inside which shows...
Abstract We report observations from the Magnetospheric Multiscale satellites of large‐amplitude, parallel, electrostatic waves associated with magnetic reconnection at Earth's magnetopause. The observed have parallel electric fields ( E || ) amplitudes on order 100 mV/m and display nonlinear characteristics that suggest a possible net . These are within ion diffusion region adjacent to (within several electron skin depths) region. They in or near magnetosphere side current layer. Simulation...
Abstract We show observations from the Magnetospheric Multiscale (MMS) mission of whistler mode waves in Earth's low‐latitude boundary layer (LLBL) during a magnetic reconnection event. The propagated obliquely to field toward X line and were confined edge southward jet LLBL. Bipolar parallel electric fields interpreted as electrostatic solitary (ESW) are observed intermittently appear be phase with component oscillations. polarity ESWs suggests that if they propagate waves, electron...
We report observations from the Magnetospheric Multiscale satellites of parallel electric fields (E_{∥}) associated with magnetic reconnection in subsolar region Earth's magnetopause. E_{∥} events near electron diffusion have amplitudes on order 100 mV/m, which are significantly larger than those predicted for an antiparallel field. This Letter addresses specific types events, appear as large-amplitude, unipolar spikes that tangled, reconnected fields. These primarily or a current layer...
Abstract Observations of magnetic reconnection at Earth's magnetopause often display asymmetric structures that are accompanied by strong field ( B ) fluctuations and large‐amplitude parallel electric fields E || ). The turbulence is most intense frequencies above the ion cyclotron frequency below lower hybrid frequency. consistent with a thin, oscillating current sheet corrugated along electron flow direction (along X line), which type electromagnetic drift wave. Near line, primarily due to...
Abstract Small‐scale magnetic holes (MHs), local depletions in field strength, have been observed multiple times the Earth's magnetosphere bursty bulk flow (BBF) braking region. This particular subset of MHs has scale sizes perpendicular to background ( B ) less than ambient ion Larmor radius ρ i ). Previous observations by Time History Events and Macroscale Interactions during Substorms (THEMIS) indicate that this can be supported a current driven E × drift electrons. Ions do not...
We present an extensive search for RR Lyrae stars in and around the ultra-faint Milky Way companions Segue 2 3. The former (M_V = -2.5, Belokurov et al. 2009) appears to be extremely faint dwarf galaxy companion of Way. latter 0.0, Fadely 2011) is among faintest star clusters known. use B V band time-series imaging obtained at WIYN 0.9 meter telescope Kitt Peak National Observatory these objects. In our observations, we a previously unknown fundamental mode (RRab) with period P_ab 0.748...
Abstract On 8 September 2015, the four Magnetospheric Multiscale spacecraft encountered a Kelvin‐Helmholtz unstable magnetopause near dusk flank. The observed periodic compressed current sheets, between which plasma was turbulent. We present observations of large‐amplitude (up to 100 mV/m) oscillations in electric field. Because these are purely parallel background magnetic field, electrostatic, and below ion frequency, they likely be acoustic‐like waves. These waves turbulent where multiple...
Five spacecraft-plasma models are used to simulate the interaction of a simplified geometry Solar Probe Plus (SPP) satellite with space environment under representative solar wind conditions near perihelion. By considering similarities and differences between results obtained different numerical approaches well defined conditions, consistency validity our can be assessed. The impact on model predictions physical effects importance in SPP mission is also considered by comparing without these...
Abstract We report multispacecraft observations by the Magnetospheric MultiScale (MMS) mission of large (80–155 λ De parallel to B ) electrostatic solitary waves (ESWs). Observations same ESWs at different positions and times enable unprecedented accuracy in determining size, velocity, evolution these nonlinear structures. This particular event is a short series negative potential magnetosheath. The observed structures differ amplitude speed, merging or colliding with one another. A Vlasov...
Chorus waves are important for electron energization and loss in Earth's radiation belts inner magnetosphere. Because the amplitude spatial distribution of chorus can be strongly influenced by plasma density fluctuations spacecraft floating potential a diagnostic density, relationship between measured is examined using Van Allen Probes data. While wave electric fields correlate strongly, fluctuation properties found not to consistent with on timescales individual packets. Instead, enhanced...
Abstract Two magnetopause current sheet crossings with tripolar guide magnetic field signatures were observed by multiple Magnetosphere Multiscale (MMS) spacecraft during Kelvin‐Helmholtz wave activity. The two out‐of‐plane depressions of the are largely supported in‐plane electron currents, which reminiscent clockwise Hall loop systems. A comparison a three‐dimensional kinetic simulation waves and vortex‐induced reconnection suggests that MMS likely encountered on either side X‐line....