A5016753275- Ionosphere and magnetosphere dynamics
- Earthquake Detection and Analysis
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- GNSS positioning and interference
- Meteorological Phenomena and Simulations
- Oceanographic and Atmospheric Processes
- Geophysics and Gravity Measurements
- Atmospheric Ozone and Climate
- Astro and Planetary Science
- Atmospheric aerosols and clouds
- Ocean Waves and Remote Sensing
- Precipitation Measurement and Analysis
- Radio Astronomy Observations and Technology
- Seismic Waves and Analysis
- Climate variability and models
- Lightning and Electromagnetic Phenomena
- Laser-induced spectroscopy and plasma
- Atmospheric and Environmental Gas Dynamics
- Infrared Target Detection Methodologies
- Tropical and Extratropical Cyclones Research
- Geophysics and Sensor Technology
- Calibration and Measurement Techniques
- Ocean Acidification Effects and Responses
- Planetary Science and Exploration
Clemson University
2019-2025
SRI International
2014-2022
University of Iowa
2012-2022
Goddard Space Flight Center
2011-2022
University of Scranton
2022
New Jersey Institute of Technology
2022
Menlo School
2014-2016
Abstract We demonstrate a novel method for observing Large Scale Traveling Ionospheric Disturbances (LSTIDs) using high frequency (HF) amateur radio reporting networks, including the Reverse Beacon Network (RBN), Weak Signal Propagation Reporter (WSPRNet), and PSKReporter. LSTIDs are quasi‐periodic variations in ionospheric densities with horizontal wavelengths >1,000 km periods between 30 180 min. On Nov 3, 2017, LSTID signatures were observed simultaneously over continental United...
The impact of regional-scale neutral atmospheric waves has been demonstrated to have profound effects on the ionosphere, but circumstances under which they generate ionospheric disturbances and seed plasma instabilities are not well understood. Neutral vary from infrasonic <20 Hz gravity with periods order 10 min, for simplicity, hereafter combined common term Acoustic Gravity Waves (AGWs). There other longer period like planetary lower middle atmosphere, whose important globally,...
Abstract In this paper, we investigated the seasonal and geomagnetic dependence of auroral ‐region neutral winds tidal components between 90 125 km using nearly continuously sampled measurements from Poker Flat Incoherent Scatter Radar (PFISR) 2010 to 2019. The average show consistent semidiurnal oscillations 100 115 diurnal above in all seasons with some activity dependencies. general, oscillation zonal meridional directions is strongest summer weakest winter. winter spring. More details on...
The term “Medium-Scale Traveling Ionospheric Disturbances” is used to describe a number of different propagating phenomena in ionospheric plasma density with scale size hundreds km. This includes multiple generation mechanisms, including ion-neutral collisions, instabilities, and electromagnetic forcing. Observational limitations can impede characterization identification MSTID mechanisms. We discuss inconsistencies the current terminology these provide set recommendations for description discussion.
Abstract The high‐latitude E‐region wind forcing has been studied extensively at large scales, but studies in auroral‐oval‐width scales are still sparse. In the auroral region, where magnetospheric is scale size of aurora, winds can be forced to hundreds meters per second acceleration channel. This result advective accelerations, even a moderate cross‐channel neutral could move momentum outside channel through advection. this paper, we use sounding rocket data from Alaska estimate meridional...
Abstract Geomagnetic storms transfer massive amounts of energy from the sun to geospace. Some that is dissipated in ionosphere as energetic particles precipitate and their atmosphere, creating aurora. We used Time History Events Macroscale Interactions during Substorms (THEMIS) mosaic all‐sky‐imagers across Canada Alaska measure amount flux deposited into via auroral precipitation 2013 March 17 storm. determined time‐dependent percent total contributed by meso‐scale (<500 km wide)...
Abstract We present three case studies that examine optical and radar methods for specifying precipitating auroral flux parameters conductances. Three events were chosen corresponding to moderate nonsubstorm activity with 557.7 nm intensities greater than 1kR. A technique directly fits the electron number density from a forward transport model alternating code incoherent scatter data is presented. method determining characteristic energy using neutral temperature observations compared...
Abstract Amateur radio reporting networks, such as the Reverse Beacon Network (RBN), PSKReporter, and Weak Signal Propagation Network, are powerful tools for remote sensing ionosphere. These voluntarily constructed operated networks provide real‐time archival data that could be used space weather operations, forecasting, research. The potential exists study of both global localized effects. capability one network to detect disturbances is demonstrated by examining impacts on RBN‐observed HF...
An important question that is being increasingly studied across subdisciplines of Heliophysics “how do mesoscale phenomena contribute to the global response system?” This review paper focuses on this within two specific but interlinked regions in Near-Earth space: magnetotail’s transition region inner magnetosphere and ionosphere. There a concerted effort Geospace Environment Modeling (GEM) community understand degree which transport magnetotail contributes dynamics magnetic flux...
Abstract Field‐aligned currents from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) were combined with simultaneous coincident observations of ionospheric conductivities made by Poker Flat Incoherent Scatter Radar (PFISR) in Alaska for 20 geomagnetically active days. The height‐integrated (conductances) determined electron densities measured radar between 80 200 km altitude. Binning averaging data field‐aligned current density magnetic local time, we find...
Recent attention has been given to mesoscale phenomena across geospace (∼10 s km 500 in the ionosphere or ∼0.5 R E several magnetosphere), as their contributions system global response are important yet remain uncharacterized mostly due limitations data resolution and coverage well computational power. As models improve, it becomes increasingly valuable advance understanding of role contributions—specifically, magnetosphere-ionosphere coupling. This paper describes a new method that utilizes...
Quantification of energetic electron precipitation caused by wave-particle interactions is fundamentally important to understand the cycle particle energization and loss radiation belts. One way determine how well interaction models predict losses through pitch-angle scattering into atmospheric cone direct comparison between ionization altitude profiles expected in atmosphere due precipitating fluxes actually measured with incoherent scatter radars. This paper reports such a using forward...
The ACES‐High rocket, part of the Auroral Current and Electrodynamics Structure (ACES) mission launched from Poker Flat Research Range on 29 January 2009, obtained first in situ measurements indicative both observational characteristics associated with ionospheric feedback instability as it flew through an auroral arc its return current region. observed Alfvénic wave structures localized areas roughly 10 km near boundaries region discrete increased electron density a temperature...
Abstract Precipitating auroral electrons can produce discrete arcs that contain signatures of the magnetospheric source region. Differential number flux observations over two aurorae were obtained by Auroral Currents and Electrodynamics Structure sounding rocket mission, which successfully launched in 2009. These made at E region altitudes approximately 130 km. A model precipitating as described Evans (1974) was fit to electron differential payloads, parameters from used infer properties It...
Abstract Plasmaspheric hiss can cause energetic electron precipitation from the magnetosphere to Earth's upper atmosphere and affect ionospheric density profiles. In this study, we use Arase satellite measurements in dayside plasmasphere model resultant response, compare results measured by Poker Flat Incoherent Scatter Radar (PFISR). We analyzed two close conjunction events between PFISR at L ∼ 6 afternoon sector, when was outer traveled into plasmaspheric plumes. Modest or strong waves...
Pulsating aurora are common diffuse-like aurora. Studies have suggested that they contain higher energy particles than other types and possibly linked to substorm activity. There has yet be a quantitative statistical study of the variation in pulsating content related substorms. We analyzed inverted from 53 events using Poker Flat Incoherent Scatter Radar. To reduce uncertainty, we split differential flux into low high limit 30 keV. also lower altitude boundary electron density profile,...
Abstract As one of the strongest geomagnetic storms in Solar Cycle 24, 2015 St. Patrick's Day storm has attracted significant attention. We revisit this event by taking advantage simultaneous observations high‐latitude forcings (aurora and electric fields) ionosphere‐thermosphere (I‐T) responses. The forcing terms are assimilated to drive Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM) using a newly adopted Lattice Kriging method (Wu & Lu, 2022,...
Abstract We present empirical conductance relations that are derived from incoherent scatter radar observations and correlated with all sky imager to identify the morphology of aurora. use 75,461 events collected using Poker Flat Incoherent Scatter Radar (PFISR) associated imagers spanning years 2012–2016. In addition classifying these based on auroral morphology, we estimated Hall Pedersen differential number flux which energy average can be calculated. The was maximum entropy inversion...
Abstract A variety of statistical studies have shown that the ionospheric polar potential produced by solar wind‐magnetosphere‐ionosphere coupling is linear for weak to moderate wind driving but becomes nonlinear during periods very strong driving. It has been this applies two‐cell convection develops southward interplanetary magnetic field (IMF) and also reverse cells develop northward IMF. This described as saturation, it appears begin when electric greater than 3 mV/m. Utilizing...
Abstract We present new results using data collected by the Poker Flat Incoherent Scatter Radar (PFISR) of energy transfer rates, which include effects from neutral winds in high latitude E‐region ionosphere‐thermosphere (IT) during Fall 2015. The purpose our investigation is to understand magnetic local time (MLT) dependence peak transfer, occurs asymmetrically morning‐evening (dawn‐dusk) MLT sector. statistical characteristics both altitude‐resolved and altitude‐integrated rates auroral E...
We present a Python implementation of D- and E-region chemistry ionization code called pyGPI5. Particle precipitation that penetrates into the E- D-region ionosphere-thermosphere causes significant enhancements electron density. Dissociative recombination molecular ions with electrons is primary loss mechanism in E-region, down to approximately 85 km. However, below km, chemical processes become significantly more complicated positive negative being generated addition electrons. The complex...
Abstract As part of its International Capabilities Assessment effort, the Community Coordinated Modeling Center initiated several working teams, one which is focused on validation models and methods for determining auroral electrodynamic parameters, including particle precipitation, conductivities, electric fields, neutral density winds, currents, Joule heating, boundaries, ion outflow. Auroral properties are needed as input to space weather models, test validate accuracy physical provide...
Abstract We use the Geospace Environment Model of Ion‐Neutral Interactions (GEMINI) to create three‐dimensional, time‐dependent simulations auroral ionospheric parameters in localized, several 100 km region surrounding arcs observed during a winter 2017 sounding rocket campaign, resolving three‐dimensional features fine‐scale (km) flow structures vicinity an arc. The calculations GEMINI allow (with sufficient driving data) current closure be investigated without idealizing assumptions...