Evaluating a Power Grid's Vulnerability to High Altitude Electromagnetic Pulses Using Detailed Earth Conductivity Models

A nuclear bomb detonated above the earth’s surface can cause a high-altitude electromagnetic pulse (HEMP). HEMPs create an electric field at the earth’s surface, which induces unwanted slowly varying dc currents, called geomagnetically induced currents (GIC) on transmission lines. The magnitude of the electric field highly depends on the conductivity of the earth, hundreds of thousands of meters below the surface. The earth’s conductivity is very complex and there exist different models to represent it. HEMP electric fields are commonly evaluated using a simple model called the uniform model, which models the earth using a single value of conductivity. This thesis describes a method to convert HEMP electric fields under a more detailed conductivity model, called the 1D model, which is based on geological surveys and includes regional variations. Using the 1D model enables locationally dependent simulations of HEMP electric fields, yielding more realistic results. This methodology has been automated by a tool, created with MATLAB, and was applied to several publicly available HEMP electric field waveforms at different locations across the continental United States. These electric fields are analyzed by comparing their magnitudes and their impact on a 10,000-bus synthetic grid. The results show the extent that HEMP electric field magnitudes can vary from region to region. Also, evaluations of different HEMP electric field waveforms show that each waveform may have characteristics that impact the grid differently. Based on the analysis performed in this thesis, it is recommended that comprehensive HEMP vulnerability studies utilize multiple worst-case HEMP waveforms while considering regional differences in earth conductivity

Developing a UK new ground electric field model for SWIMMR N4 (SAGE) : interim report

This interim report describes progress made to date in the SWIMMR N4 (SAGE) project regarding the update of geoelectric field modelling in Britain during magnetic storms. We describe research efforts to understand how the present thin-sheet method of computing the geoelectric field from magnetic variation data compares to the measured field at the three UK observatories. We then examine how measured magnetotelluric (MT) impedances can be used to improve the modelled geoelectric field during space weather events. Next, we describe the fieldwork campaign to collect new high quality magnetotelluric data in Britain. As of August 2022, BGS have collected magnetic and electric field measurements at 32 sites across England, southern Scotland, and Wales. Around 18 remain to be completed by March 2023. We present results from all the sites collected thus far. The measurements have been used to compute MT impedances which demonstrate large variability attributed to the underlying geology across Britain. We use the new MT data to re-evaluate the geoelectric field during the September 2017 storm and find large differences, for example, in central Yorkshire the electric field estimates are about one-tenth the magnitude observed in Lincolnshire around 100 km distant. In the future the MT measurements will be included in a new 3D model of the conductivity of Britain for space weather hazard purposes

Considerations for Real Time Data Analysis Using Multiple Magnetometer Sources for GIC Studies to Improve the Situational Awareness of an Electric Grid Model

This thesis aims to effectively utilize actual historical and real-time data to enhance electric grid model knowledge by reconstructing GMD scenarios. Magnetic and electric field data used for the analysis are generated and calculated from Texas A&M Magnetometer Network (TAMUMN). Days of GMD activity (G2, G1) during the past year are selected to reconstruct events with similar data on a synthetically developed version of the Texas electric grid with 7000 bus network. Upon integrating the data to a simulated power system model, the impact of geomagnetically induced currents (GIC) can be determined. By performing certain power system analysis techniques, the most affected regions, magnitudes of maximum current at substations and the transmission lines with the highest activity can be obtained. This is greatly useful for planning purposes and studies as it directs the user to focus on a specific section of the grid model and works toward strengthening it

Magnetotelluric Studies of Tectonic Systems and Volcanic Areas of North America

Magnetotellurics is used in two geologic settings on scales ranging from 1000-km tectonic structures to local features hundreds of meters wide. These areas are the Midcontinent Rift System (MRS) and its related mantle plume in the northern Midwestern United States and Newberry Volcano in central Oregon. The MRS study uses MT data to image structures of the midcrust to the upper mantle. In addition to the rift, an elongated conductor is present at the base of the lithosphere, interpreted as the hot spot track from the mantle plume that initiated rifting. This track terminates in southern Wisconsin at the 1.8-1.7 Ga Yavapai-Mazatzal accretion that was contemporaneous with a major change in the chemistry of subducted material. During this time, conductive sediment rich in metallic sulfide minerals that recorded a change in global ocean chemistry from iron-saturated to sulfur-saturated during the Proterozoic Great Oxygenation Event was deposited on the seafloor. Melting of sediment rich in metallic sulfide minerals during the onset of the Keweenaw mantle plume that initiated the MRS in western Lake Superior enabled interconnection of disseminated sulfide crystals to produce a hot spot track at upper lithospheric depths that are in agreement with melting depths and temperatures inferred from petrologic studies of syn-rift flood basalts. The hot spot’s location shows that pre-Yavapai accretion subduction was north-dipping and low-angle. The Newberry work shows that magma within the caldera is unusually resistive and therefore must be felsic and dry if it is to agree with seismic models and with the petrology of recent eruptions. Using seismic and petrological constraints, we find that the magma reservoir has no more than 8.7% partial melt. A major component of the volcano’s hydrothermal system is expressed along the caldera’s south rim as a vertical conductive anomaly reaching from the magma chamber to the vent that produced the most recent eruption

Understanding space weather to shield society: A global road map for 2015-2025 commissioned by COSPAR and ILWS

There is a growing appreciation that the environmental conditions that we call space weather impact the technological infrastructure that powers the coupled economies around the world. With that comes the need to better shield society against space weather by improving forecasts, environmental specifications, and infrastructure design. [...] advanced understanding of space weather requires a coordinated international approach to effectively provide awareness of the processes within the Sun-Earth system through observation-driven models. This roadmap prioritizes the scientific focus areas and research infrastructure that are needed to significantly advance our understanding of space weather of all intensities and of its implications for society. Advancement of the existing system observatory through the addition of small to moderate state-of-the-art capabilities designed to fill observational gaps will enable significant advances. Such a strategy requires urgent action: key instrumentation needs to be sustained, and action needs to be taken before core capabilities are lost in the aging ensemble. We recommend advances through priority focus (1) on observation-based modeling throughout the Sun-Earth system, (2) on forecasts more than 12 hrs ahead of the magnetic structure of incoming coronal mass ejections, (3) on understanding the geospace response to variable solar-wind stresses that lead to intense geomagnetically-induced currents and ionospheric and radiation storms, and (4) on developing a comprehensive specification of space climate, including the characterization of extreme space storms to guide resilient and robust engineering of technological infrastructures. The roadmap clusters its implementation recommendations by formulating three action pathways, and outlines needed instrumentation and research programs and infrastructure for each of these. [...]Comment: In press for Advances of Space Research: an international roadmap on the science of space weather, commissioned by COSPAR and ILWS (63 pages and 4 figures

Ionosphere Monitoring with Remote Sensing

This book focuses on the characterization of the physical properties of the Earth’s ionosphere, contributing to unveiling the nature of several processes responsible for a plethora of space weather-related phenomena taking place in a wide range of spatial and temporal scales. This is made possible by the exploitation of a huge amount of high-quality data derived from both remote sensing and in situ facilities such as ionosondes, radars, satellites and Global Navigation Satellite Systems receivers

Ground-based and additional science support for SMILE

The joint European Space Agency and Chinese Academy of Sciences Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) mission will explore global dynamics of the magnetosphere under varying solar wind and interplanetary magnetic field conditions, and simultaneously monitor the auroral response of the Northern Hemisphere ionosphere. Combining these large-scale responses with medium and fine-scale measurements at a variety of cadences by additional ground-based and space-based instruments will enable a much greater scientific impact beyond the original goals of the SMILE mission. Here, we describe current community efforts to prepare for SMILE, and the benefits and context various experiments that have explicitly expressed support for SMILE can offer. A dedicated group of international scientists representing many different experiment types and geographical locations, the Ground-based and Additional Science Working Group, is facilitating these efforts. Preparations include constructing an online SMILE Data Fusion Facility, the discussion of particular or special modes for experiments such as coherent and incoherent scatter radar, and the consideration of particular observing strategies and spacecraft conjunctions. We anticipate growing interest and community engagement with the SMILE mission, and we welcome novel ideas and insights from the solar-terrestrial community

Optical Remote Sensing of Mesoscale Thermospheric Dynamics Above Svalbard and Kiruna

Vertical winds are key in thermospheric dynamics and only until recently have the detectors been sensitive enough for them to be measured accurately. Two narrow field Fabry-Perot Interferometers (FPIs) are used as well as one state-of-the-art all-sky FPI, SCANning Doppler Imager (SCANDI), which is capable of simultaneous measurements across the sky at high spatial and temporal resolution. They measure the atomic oxygen 630nm emission line which peaks in brightness at 240km altitude in the upper thermosphere region. Emission intensities, line-of-sight wind speeds and neutral temperatures are obtained. SCANDI’s existing infrastructure has been developed based upon the requirement to upgrade the sky map to higher spatial resolution, for the onset of solar maximum. The calibration methods and data analysis are presented. The wind-fitting algoithm is shown for the new map trigonometry. This fitting is verified by producing climatological horizontal wind-fields in a dial plot format and cross-comparing with SuperDARN climatologies. A statistical analysis of the vertical winds from 2002-2009 is presented leading to the possibility of ‘black swan events’ around midnight in the polar cap. These are events which are thought impossible but are, in reality, found to have a small finite chance of occurrence. An investigation into the mechanism of the generation of these events leads to the discovery of hydroxyl contamination in the Svalbard data set. A spectral simulation of the 630nm and the hydroxyl lines allows the determination of an emission intensity threshold of 40R (10R) below which the wind (temperature) values are significantly affected. The Svalbard data set is re-analysed excluding the contaminated data and a clean, more reasonable data set is presented with no black swan events. A statistical study of the relationship between the vertical and horizontal components of wind is presented showing the Burnside relationship is unsuitable for representing highlatitude winds. The CMAT2 atmosphere model data is used to assess which of Burnside et al’s (1982) assumptions are violated. The CUSPN campaign is presented showing the first results of the charged and neutral cusp region being simultaneously and independently measured using the EISCAT Svalbard Radar and the FPIs. Characteristic upwellings are observed concurrent with cusp precipitation and flux transfer events, which provides compelling evidence of high altitude ion-frictional heating

A Generation Prioritization Method for Power System Restoration with Renewable Resources

The electrical grid is a key component of the Nation's critical infrastructure. Its continuous and reliable operation is of vital importance; any system-wide disruption would have a debilitating impact on crucial services, public health and safety, the economy, and the national security of the United States. High-impact low-frequency events pose the greatest threat to the grid due to their severity and unpredictability; these may be caused by naturally occurring hazards (e.g., earthquakes, solar storms, extreme weather conditions) or acts of human volition (e.g., malicious cyber-, or coordinated set of physical attacks). To improve the resilience of the grid against such threats and enhance the protection of the critical infrastructure, this research examines ways in which power system restoration processes are considerably accelerated. A new generation prioritization method is proposed for time-sensitive system restorations, which significantly shortens the total restoration times. To achieve this, available renewable generation is leveraged and an algorithm is developed that plans the optimal operational schedule of the system close to real time. Benchmarking and validation experiments are performed on test systems modeled after the electrical grid of the U.S. Pacific Northwest, and prove that this convenient toolset supports a quick recovery, faster than other common approaches