Publications

2022
Blandin M, Connor HK, Öztürk DS, Keesee AM, Pinto V, Mahmud MS, Ngwira C, Priyadarshi S. Multi-Variate LSTM Prediction of Alaska Magnetometer Chain Utilizing a Coupled Model Approach. Frontiers in Astronomy and Space Sciences. 2022;9 (May) :846291.
Siddique T, Mahmud MS, Keesee AM, Ngwira CM, Connor H. A Survey of Uncertainty Quantification in Machine Learning for Space Weather Prediction. Geosciences (Switzerland). 2022;12 (1) :1–23.Abstract
With the availability of data and computational technologies in the modern world, machine learning (ML) has emerged as a preferred methodology for data analysis and prediction. While ML holds great promise, the results from such models are not fully unreliable due to the challenges introduced by uncertainty. An ML model generates an optimal solution based on its training data. However, if the uncertainty in the data and the model parameters are not considered, such optimal solutions have a high risk of failure in actual world deployment. This paper surveys the different approaches used in ML to quantify uncertainty. The paper also exhibits the implications of quantifying uncertainty when using ML by performing two case studies with space physics in focus. The first case study consists of the classification of auroral images in predefined labels. In the second case study, the horizontal component of the perturbed magnetic field measured at the Earth's surface was predicted for the study of Geomagnetically Induced Currents (GICs) by training the model using time series data. In both cases, a Bayesian Neural Network (BNN) was trained to generate predictions, along with epistemic and aleatoric uncertainties. Finally, the pros and cons of both Gaussian Process Regression (GPR) models and Bayesian Deep Learning (DL) are weighed. The paper also provides recommendations for the models that need exploration, focusing on space weather prediction.
2021
Adewuyi M, Keesee AM, Nishimura Y, Gabrielse C, Katus RM. Mesoscale Features in the Global Geospace Response to the March 12, 2012 Storm. Frontiers in Astronomy and Space Sciences. 2021;8 (October) :746459.Abstract
The geospace response to coronal mass ejections includes phenomena across many regions, from reconnection at the dayside and magnetotail, through the inner magnetosphere, to the ionosphere, and even to the ground. Phenomena occurring in each region are often connected to each other through the magnetic field, but that field undergoes dynamic changes during storms and substorms. Improving our understanding of the geospace response to storms requires a global picture that enables us to observe all the regions simultaneously with both spatial and temporal resolution. Using the Energetic Neutral Atom (ENA) imager on the Two Wide-Angle Imaging Neutral-Atom Spectrometers (TWINS) mission, a temperature map can be calculated to provide a global view of the magnetotail. These maps are combined with in situ measurements at geosynchronous orbit from GOES 13 and 15, auroral images from all sky imagers (ASIs), and ground magnetometer measurements to examine the global geospace response of a coronal mass ejection (CME) driven event on March 12th, 2012. Mesoscale features in the magnetotail are observed throughout the interval, including prior to the storm commencement and during the main phase, which has implications for the dominant processes that lead to pressure buildup in the inner magnetosphere. Auroral enhancements that can be associated with these magnetotail features through magnetosphere-ionosphere coupling are observed to appear only after global reconfigurations of the magnetic field.
Keesee AM, Buzulukova N, Mouikis C, Scime EE. Mesoscale structures in Earth's magnetotail observed using energetic neutral atom imaging. Geophysical Research Letters. 2021;48 :e2020GL091467.
Farrugia CJ, Rogers AJ, Torbert RB, Genestreti KJ, Nakamura TKM, Lavraud B, Montag P, Egedal J, Payne D, Keesee A, et al. An Encounter With the Ion and Electron Diffusion Regions at a Flapping and Twisted Tail Current Sheet. Journal of Geophysical Research: Space Physics. 2021;126 (3) :1–23.Abstract
We analyze data returned by the Magnetospheric Multiscale mission (MMS) constellation during a rapid (∼1.5 s) traversal of a flapping and reconnecting current sheet (CS) in the near-Earth magnetotail (X ∼−20 RE). The CS was highly tilted, with its normal pointing strongly duskward. Its extreme thinness was confirmed by a curvature analysis of the magnetic field lines. The event was associated with a guide field of 8% of the reconnecting components. From the pitch angle distributions of low-energy electrons we infer a crossing earthward of the X-line. Traveling practically normal to the CS, MMS encountered an ion diffusion region (IDR) in which was embedded an electron diffusion region (EDR). IDR signatures included breaking of the ion frozen-in condition in the presence of Hall B and E fields. EDR signatures included a strong out-of-plane current associated with a superAlfvénic electron jet, positive energy transfer, and a temperature anisotropy (Te∥ > Te⊥) which disappeared at the field reversal. Derived scale sizes normal to the CS are: ∼6.9 de (EDR) and ∼0.4 di (IDR; 40 and 100 km). We estimate the average dimensionless reconnection rate as 0.077 ± 0.050. The observations and inferences are supported by particle-in-cell (PIC) numerical simulations. We find very good agreement in the reconnection rates. We also discuss the effects of asymmetries in the density, temperature and magnetic field strength on the Hall fields and length of the outflow jets. The event is associated with a substorm onset which began 7 min after the MMS observations.
Keesee AM, Buzulukova N, Mouikis C, Scime EE. Mesoscale structures in Earth's magnetotail observed using energetic neutral atom imaging. Geophysical Research Letters. 2021;48 :e2020GL091467.
2020
Keesee AM, Katus RM, Floyd M, Scime E. Database of storm-time equatorial ion temperatures in Earth's magnetosphere calculated from energetic neutral atom data. Journal of Geophysical Research : Space Physics. 2020;125 :1–9.
Keesee AM, Buzulukova N, Mouikis C, Scime EE. Mesoscale structures in Earth's magnetotail observed using energetic neutral atom imaging. Geophysical Research Letters. 2020;(2002) :1–8.
Keesee AM, Pinto V, Coughlan M, Lennox C, Mahmud S, Connor HK. Comparison of Deep Learning Techniques to Model Connections Between Solar Wind and Ground Magnetic Perturbations. Frontiers in Astronomy and Space Sciences. 2020;7 (October) :550874.
Keesee A, Katus RM, Floyd M, Scime E. Database of storm-time equatorial ion temperatures in Earth's magnetosphere calculated from energetic neutral atom data. Journal of Geophysical Research : Space Physics. 2020;125 :1–9.
2019
Keesee A, Scime E, Zaniewski A, Katus R. 2D Ion Temperature Maps from TWINS ENA data: IDL scripts. 2019.
Keesee AM, Williamson K, Robertson-Honecker J. Community Based Solar Eclipse Outreach in Rural Appalachia. In: Buxner S, Shore L, Jensen J Celebrating the 2017 Great American Eclipse: Lessons Learned from the Path of Totality. Vol. 516. Astronomical Society of the Pacific ; 2019. pp. 77–83. Publisher's Version
Scime EE, Keesee AM. Enhanced Energetic Neutral Atom Imaging. Frontiers in Astronomy and Space Sciences [Internet]. 2019;6 (February) :1–5. Publisher's Version
2018
Thompson DS, Steinberger TE, Keesee AM, Scime EE. Laser induced fluorescence of Ar-I metastables in the presence of a magnetic field. Plasma Sources Science and Technology. 2018;27 (6).
Keesee AM, Dugas M, Ellison S, Neal L, Scime EE, Thompson DS, Tersteeg J, Tucker CJ. Micro-spectrometer for fusion plasma boundary measurements. Review of Scientific Instruments [Internet]. 2018;89 (10) :10J116. Publisher's Version
2017
Keesee AM, Katus RM, Scime EE. The Effect of Storm Driver and Intensity on Magnetospheric Ion Temperatures. Journal of Geophysical Research: Space Physics [Internet]. 2017;122 (9) :9414–9426. Publisher's VersionAbstract
©2017. American Geophysical Union. All Rights Reserved. Energy deposited in the magnetosphere during geomagnetic storms drives ion heating and convection. Ions are also heated and transported via internal processes throughout the magnetosphere. Injection of the plasma sheet ions to the inner magnetosphere drives the ring current and, thus, the storm intensity. Understanding the ion dynamics is important to improving our ability to predict storm evolution. In this study, we perform superposed epoch analyses of ion temperatures during storms, comparing ion temperature evolution by storm driver and storm intensity. The ion temperatures are calculated using energetic neutral atom measurements from the Two Wide-Angle Imaging Neutral-Atom Spectrometers (TWINS) mission. The global view of these measurements provide both spatial and temporal information. We find that storms driven by coronal mass ejections (CMEs) tend to have higher ion temperatures throughout the main phase than storms driven by corotating interaction regions (CIRs) but that the temperatures increase during the recovery phase of CIR-driven storms. Ion temperatures during intense CME-driven storms have brief intervals of higher ion temperatures than those during moderate CME-driven storms but have otherwise comparable ion temperatures. The highest temperatures during CIR-driven storms are centered at 18 magnetic local time and occur on the dayside for moderate CME-driven storms. During the second half of the main phase, ion temperatures tend to decrease in the postmidnight to dawn sector for CIR storms, but an increase is observed for CME storms. This increase begins with a sharp peak in ion temperatures for intense CME storms, likely a signature of substorm activity that drives the increased ring current.
Keesee AM, Katus RM, Scime EE. The Effect of Storm Driver and Intensity on Magnetospheric Ion Temperatures. Journal of Geophysical Research: Space Physics. 2017;122 (9) :9414–9426.Abstract
©2017. American Geophysical Union. All Rights Reserved. Energy deposited in the magnetosphere during geomagnetic storms drives ion heating and convection. Ions are also heated and transported via internal processes throughout the magnetosphere. Injection of the plasma sheet ions to the inner magnetosphere drives the ring current and, thus, the storm intensity. Understanding the ion dynamics is important to improving our ability to predict storm evolution. In this study, we perform superposed epoch analyses of ion temperatures during storms, comparing ion temperature evolution by storm driver and storm intensity. The ion temperatures are calculated using energetic neutral atom measurements from the Two Wide-Angle Imaging Neutral-Atom Spectrometers (TWINS) mission. The global view of these measurements provide both spatial and temporal information. We find that storms driven by coronal mass ejections (CMEs) tend to have higher ion temperatures throughout the main phase than storms driven by corotating interaction regions (CIRs) but that the temperatures increase during the recovery phase of CIR-driven storms. Ion temperatures during intense CME-driven storms have brief intervals of higher ion temperatures than those during moderate CME-driven storms but have otherwise comparable ion temperatures. The highest temperatures during CIR-driven storms are centered at 18 magnetic local time and occur on the dayside for moderate CME-driven storms. During the second half of the main phase, ion temperatures tend to decrease in the postmidnight to dawn sector for CIR storms, but an increase is observed for CME storms. This increase begins with a sharp peak in ion temperatures for intense CME storms, likely a signature of substorm activity that drives the increased ring current.
Keesee AM. A review of dawn-dusk asymmetries observed using the TWINS mission of opportunity. Dawn-Dusk Asymmetries in Planetary Plasma Environments. 2017 :213–221.Abstract
The NASA Two Wide-Angle Imaging Neutral Atom Spectrometers (TWINS) Mission of Opportunity is the first stereoscopic imaging mission of the magnetosphere. Each of two satellites hosts an energetic neutral atom (ENA) imager and a Lyman-alpha detector (LAD). The remote detection nature of these two instruments enables TWINS to make global observations of the magnetosphere. Such global measurements provide an excellent platform for the study of dawn-dusk asymmetries that appear in many characteristics of the magnetosphere. This work reviews the studies using TWINS data that have discussed dawn-dusk asymmetries over the past 7 years, expanding upon the review of the first 5 years of the mission by Goldstein and McComas [2013], while focusing specifically on the analysis of the asymmetries.
Keesee AM, Katus RM, Scime EE. The Effect of Storm Driver and Intensity on Magnetospheric Ion Temperatures. Journal of Geophysical Research: Space Physics. 2017;122 (9).Abstract
©2017. American Geophysical Union. All Rights Reserved. Energy deposited in the magnetosphere during geomagnetic storms drives ion heating and convection. Ions are also heated and transported via internal processes throughout the magnetosphere. Injection of the plasma sheet ions to the inner magnetosphere drives the ring current and, thus, the storm intensity. Understanding the ion dynamics is important to improving our ability to predict storm evolution. In this study, we perform superposed epoch analyses of ion temperatures during storms, comparing ion temperature evolution by storm driver and storm intensity. The ion temperatures are calculated using energetic neutral atom measurements from the Two Wide-Angle Imaging Neutral-Atom Spectrometers (TWINS) mission. The global view of these measurements provide both spatial and temporal information. We find that storms driven by coronal mass ejections (CMEs) tend to have higher ion temperatures throughout the main phase than storms driven by corotating interaction regions (CIRs) but that the temperatures increase during the recovery phase of CIR-driven storms. Ion temperatures during intense CME-driven storms have brief intervals of higher ion temperatures than those during moderate CME-driven storms but have otherwise comparable ion temperatures. The highest temperatures during CIR-driven storms are centered at 18 magnetic local time and occur on the dayside for moderate CME-driven storms. During the second half of the main phase, ion temperatures tend to decrease in the postmidnight to dawn sector for CIR storms, but an increase is observed for CME storms. This increase begins with a sharp peak in ion temperatures for intense CME storms, likely a signature of substorm activity that drives the increased ring current.
Katus RM, Keesee AM, Scime E, Liemohn MW. Storm time equatorial magnetospheric ion temperature derived from TWINS ENA flux. Journal of Geophysical Research: Space Physics. 2017;122 :3985–3996.

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