Magnetohydrodynamic Electromagnetic Pulse Research Articles

Topanga: A kinetic ion plasma code for large-scale ionospheric simulations on magnetohydrodynamic timescales

Topanga is a kinetic ion code developed for simulating large-scale plasma phenomena in the Earth's ionosphere on magnetohydrodynamic timescales. It is a domain-decomposed parallel code that runs on high-performance computing platforms. Features of Topanga include spherical geometry for simplified boundary conditions and computational efficiency; a hybrid plasma model with inertia-less fluid electrons, kinetic ions, and an electric field specified via an Ohm's law; a Maxwell-FDTD (finite difference time domain) plasma model which retains the displacement current in Maxwell's equations and models electron currents in the ionosphere with a tensor conductivity; sponge-layer boundary conditions for absorption of electromagnetic and plasma waves incident on the domain boundaries; and a novel mixed-implicit algorithm for evolving the EM fields inside the Maxwell-FDTD region that is stable over many orders of magnitude in the electron–ion collision frequency. We verify the numerical methods used in Topanga on a pair of test problems. The first test involves modeling a three-dimensional collisionless shock using the hybrid set of equations. The second test involves modeling a spherical TEM mode in vacuum using the Maxwell-FDTD set of equations. Finally, we demonstrate how using the combined set of hybrid and Maxwell-FDTD equations to model the Starfish Prime high-altitude nuclear test recovers a “missing” EM signal on the ground that is not present when using only the hybrid set of equations. The magnitude of this signal in the simulation containing the Maxwell-FDTD region agrees well with the E3a portion of the magnetohydrodynamic electromagnetic pulse from Starfish Prime.

Comparison of SS-GIC and MHD-EMP-GIC effects on power systems

A comparative study of the effects of solar storm geomagnetically induced currents (SS-GIC) and nuclear detonation geomagnetically induced currents (magnetohydrodynamic electromagnetic pulse GIC or MHD-EMP-GIC) on the power system. The earth surface electric field of the MHD electromagnetic pulse is given to be of the order of 100 V/km, with a duration up to several minutes; and the electric field of the solar storms is of the order of 10 V/km, and lasts from several minutes to one hour. Both phenomena cause flow of almost direct current in the windings of power transformers through the grounding system. For long transmission lines, i.e. 300 miles or longer, this DC current offsets the 60 Hz AC and may saturate transformer cores, with secondary results such as high magnetization currents, increased harmonics, and concomitant effect on power system operation. The level of the transformer core saturation depends on the time constant of the saturation process, and on the duration and magnitude of the direct current through the transformer windings. Thus, although the solar storm electric field is much lower than MHD-EMP, the solar storm effects on the power system are greater due to their much longer duration. This paper presents a technique for the computation of the induced and/or transferred voltages and currents to an electric power system from geomagnetic disturbances. For this purpose, models of transmission lines which explicitly represent grounding, earth potential, and frequency dependent phenomena, and power transformers which explicitly represent nonlinear magnetization characteristics, are utilized.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Load flow studies in the presence of magnetohydrodynamic electromagnetic pulse

A scenario in which, seconds after a high-altitude nuclear event, the Earth's surface experiences a very low-frequency, quasi-DC magnetohydrodynamic electromagnetic pulse (MHD-EMP) field is considered. MHD-EMP fields impress quasi-DC currents on transmission and subtransmission lines. These current magnitudes can exceed several times the transformer exciting current levels. Transformers and shunt reactors experience severe half-cycle saturation resulting in harmonics and increased VAr (volt-ampere reactive) demand. The calculation of the quasi-DC currents is reviewed, the calculation of the increased VAr demand is discussed, and the effect of a simulated MHD-EMP event on a power system with stability and load flow analyses is evaluated. For the APS (Arizona Public Service) system, the simulated, base-case MHD-EMP event has major impact on power flows and voltage levels for subtransmission systems. For the base case analyzed, MHD-EMP has little effect on system stability and negligible impact on networks with DC ground paths that span small geographic distances.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Simulation of geomagnetic currents induced in a power system by magnetohydrodynamic electromagnetic pulses

The quasi-DC currents induced on a power system by a simulated magnetohydrodynamic-electromagnetic pulse (MHD-EMP) is quantified. The determination of the currents is based on the similarity between the effects of MHD-EMP and the impact of geomagnetic storms. It is shown how the methodology to calculate geomagnetic-induced currents from solar storms has been modified to calculate the currents induced by an MHD-EMP event. Results for the Arizona Public System are given. >

A Methodology to Assess the Effects of Magnetohydrodynamic Electromagnetic Pulse (MHD-EMP) on Power Systems

A Methodology to Assess the Effects of Magnetohydrodynamic Electromagnetic Pulse (MHD-EMP) on Power Systems

A Methodology to Assess the Effects of Magnetohydrodynamic Electromagnetic Pulse (MHD-EMP) on Power Systems

This paper summarizes a method to evaluate the possible effects of magnetohydrodynamic-electromagnetic pulse (MHD-EMP) on power systems. This method is based on the approach adapted to study the impact of geomagnetic storms on power systems. The paper highlights the similarities and differences between the two phenomena. Also presented are areas of concern which are anticipated from MHD-EMP on the overall system operation.