Space weather electromagnetic pulse impacts on modern smart cities and Internet of Things technologies: Observations and modeling of fast and small-scale induced currents in the context of GICs
ROSES ID: NNH19ZDA001N Selection Year: 2019
Program Element: Focused Science Topic
Principal Investigator: Mark Moldwin
Affiliation(s): niversity of Michigan
Project Member(s):
Simpson, Jamesina J Co-I/Institutional PI University of Utah, Salt Lake City
Liemohn, Michael W Co-I University Of Michigan, Ann Arbor
Summary:
We combine ground and space-based magnetometer observations with the University of Michigans Space Weather Modeling Framework (SWMF) and the University of Utahs time-domain, full-vector Maxwells equations geomagnetic field-ionosphere model to characterize the properties of fast (< a minute) geomagnetic disturbances that often precede and accompany the slower (5-10 minute) Ground-Induced Current (GIC) disturbances. We frame our work within the context of nuclear explosion (anthropogenic space weather) generated electromagnetic pulses (EMP) to highlight the similarities with geomagnetic disturbances. An EMP has three components. The early-time (E1) EMP reaches field of 50 kV/m up to 1 microsecond, the intermediate-time (E2) EMP reaches 100 V/m between 1 microsecond and a few seconds, and the late-time (E3) EMP reaches 40 V/km between 1 and several hundred seconds. E3 EMP hazards are analogous to geomagnetic storm GICs. E2 EMP have similarities with lightning and therefore most electric grid systems are protected. However, with the advent of smart grids that depend on low-voltage electronic devices, modern electronic infrastructure becomes more susceptible to faster (E1 and E2-type) disturbances that are not well studied in the context of geomagnetic disturbances. One significant difference between the faster EMP effects compared to E3/GIC is that E1/E2 electric fields couple to electronic systems directly and not through ground currents and therefore ground-conductivity plays no role in their potential impact.
The objective is to identify in 1-second ground-magnetometer data large dB/dt intervals, place them into solar wind and geomagnetic context (storm and substorm correlation) and characterize the spectral properties of the events at previously under-studied high-frequency (on the order of Hz) signatures. We will analyze decades of magnetometer data from scores of stations. Our recent studies have found: (1) that a significant fraction (40%) of the largest dB/dt events are not associated with substorms and (2) many of the largest dB/dt within the E3/GIC time domain are preceded and/or accompanied by large and more rapid fluctuations (E2). From this list, we will identify events that have both LEO (e.g., Swarm, FAST) and magnetospheric satellite (e.g., Van Allen Probes, MMS, THEMIS) observations. Though mapping uncertainties and the need to have broad conjunction criteria will make it difficult to find the same event on the ground and in space, we will characterize the field signatures (e.g., dipolarizations, compressions) and wave properties of the space-based observations to place the events into global context. We will then model select intervals with both models to understand the current and ionospheric electric field structures responsible for the fast and GIC signatures.
We will address all three primary objectives ((1) determine the space context of dB/dt, (2) characterize their temporal and spatial scales, and (3) using observations and models estimate the ideal spacing of ground-based observations) of the Magnetospheric and Ionospheric Processes Responsible for Rapid Geomagnetic Changes FST.
We contribute to five of the seven types of listed investigations: (1) Observational and numerical approaches for determining variations of GIC; (2) Numerical simulations to investigate drivers of GICs, (3) New indicators of GIC activity, (4) Analysis of satellite and ground data during GIC times; and (5) Modeling of conditions related to GICs.
Our Metrics and Milestones include developing a complete list and statistics of large dB/dt including a large number that occur outside of traditional GIC storm events, their corresponding space weather conditions, and a set of modeled events using both the UM and Utah models to examine the full-range of scales. We will work closely with the TST that overlap with our objectives to provide opportunities for reproducibility as well as unique data-model comparisons.
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