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Electron loss rates from the outer radiation belt caused by the filling of the outer plasmasphere: the calm before the storm

Description: Measurements from 7 spacecraft in geosynchronous orbit are analyzed to determine the decay rate of the number density of the outer electron radiation belt prior to the onset of high-speed-stream-driven geomagnetic storms. Superposed-data analysis is used wan(?) a collection of 124 storms. When there is a calm before the storm, the electron number density decays exponentially before the storm with a 3.4-day e-folding time: beginning about 4 days before storm onset, the density decreases from {approx}4x10{sup -4} cm{sup -3} to {approx}1X 10{sup -4} cm{sup -3}. When there is not a calm before the storm, the number-density decay is very smalL The decay in the number density of radiation-belt electrons is believed to be caused by pitch-angle scattering of electrons into the atmospheric loss cone as the outer plasmasphere fills during the calms. While the radiation-belt electron density decreases, the temperature of the electron radiation belt holds approximately constant, indicating that the electron precipitation occurs equally at all energies. Along with the number density decay, the pressure of the outer electron radiation belt decays and the specific entropy increases. From the measured decay rates, the electron flux to the atmosphere is calculated and that flux is 3 orders of magnitude less than thermal fluxes in the magnetosphere, indicating that the radiation-belt pitch-angle scattering is 3 orders weaker than strong diffusion. Energy fluxes into the atmosphere are calculated and found to be insufficient to produce visible airglow.
Date: January 1, 2009
Creator: Borovsky, Joseph E & Denton, Michael H
Partner: UNT Libraries Government Documents Department

A density-temperature description of the outer electron radiation belt during geomagnetic storms

Description: Electron flux measurements from 7 satellites in geosynchronous orbit from 1990-2007 are fit with relativistic bi-Maxwellians, yielding a number density n and temperature T description of the outer electron radiation belt. For 54.5 spacecraft years of measurements the median value ofn is 3.7x10-4 cm-3 and the median value ofT is 142 keY. General statistical properties of n, T, and the 1.1-1.5 MeV flux J are investigated, including local-time and solar-cycle dependencies. Using superposed-epoch analysis triggered on storm onset, the evolution of the outer electron radiation belt through high-speed-steam-driven storms is investigated. The number density decay during the calm before the storm is seen, relativistic-electron dropouts and recoveries from dropout are investigated, and the heating of the outer electron radiation belt during storms is examined. Using four different triggers (SSCs, southward-IMF CME sheaths, southward-IMF magnetic clouds, and minimum Dst), CME-driven storms are analyzed with superposed-epoch techniques. For CME-driven storms an absence of a density decay prior to storm onset is found, the compression of the outer electron radiation belt at time of SSC is analyzed, the number-density increase and temperature decrease during storm main phase is seen, and the increase in density and temperature during storm recovery phase is observed. Differences are found between the density-temperature and the flux descriptions, with more information for analysis being available in the density-temperature description.
Date: January 1, 2009
Creator: Borovsky, Joseph E; Cayton, Thomas E & Denton, Michael H
Partner: UNT Libraries Government Documents Department

Observations of magnetospheric substorms occurring with no apparent solar wind/IMF trigger

Description: An outstanding topic in magnetospheric physics is whether substorms are always externally triggered by disturbances in either the interplanetary magnetic field or solar wind, or whether they can also occur solely as the result of an internal magnetospheric instability. Over the past decade, arguments have been made on both sides of this issue. Horwitz and McPherron have shown examples of substorm onsets which they claimed were not externally triggered. However, as pointed out by Lyons, there are several problems associated with these studies that make their results somewhat inconclusive. In particular, in the McPherron et al. study, fluctuations in the B{sub y} component were not considered as possible triggers. Furthermore, Lyons suggests that the sharp decreases in the AL index during intervals of steady IMF/solar wind, are not substorms at all but rather that they are just enhancements of the convection driven DP2 current system that are often observed to occur during steady magnetospheric convection events. In the present study, we utilize a much more comprehensive dataset (consisting of particle data from the Los Alamos energetic particle detectors at geosynchronous orbit, IMP 8 magnetometer and plasma data, Viking UV auroral imager data, mid-latitude Pi2 pulsation data, ground magnetometer data and ISEE1 magnetic field and energetic particle data) to show as unambiguously as possible that typical substorms can indeed occur in the absence of an identifiable trigger in the solar wind/IMF.
Date: March 1, 1996
Creator: Henderson, M.G.; Reeves, G.D.; Belian, R.D. & Murphree, J.S.
Partner: UNT Libraries Government Documents Department

Hybrid modeling of the formation and structure of thin current sheets in the magnetotail

Description: Hybrid simulations are used to investigate the formation of a thin current sheet inside the plasma sheet of a magnetotail-like configuration. The initial equilibrium is subjected to a driving electric field qualitatively similar to what would be expected from solar wind driving. As a result, we find the formation of a raw current sheet, with a thickness of approximately the ion inertial length. The current density inside the current sheet region is supplied largely by the electrons. Ion acceleration in the cross-tail direction is absent due since the driving electric field fails to penetrate into the equatorial region.
Date: July 1, 1996
Creator: Hesse, M.; Winske, D. & Birn, J.
Partner: UNT Libraries Government Documents Department

Storm/substorm signatures in the outer belt

Description: The response of the ring current region is compared for periods of storm and substorm activity, with an attempt to isolate the contributions of both processes. The authors investigate CRRES particle data in an overview format that allows the display of long-term variations of the outer radiation belt. They compare the evolution of the ring current population to indicators of storm (Dst) and substorm (AE) activity and examine compositional changes. Substorm activity leads to the intensification of the ring current at higher L (L {approximately} 6) and lower ring current energies compared to storms (L {approximately} 4). The O{sup +}/H{sup +} ratio during substorms remains low, near 10%, but is much enhanced during storms (can exceed 100%). They conclude that repeated substorms with an AE {approximately} 900 nT lead to a {Delta}Dst of {approximately} 30 nT, but do not contribute to Dst during storm main phase as substorm injections do not form a symmetric ring current during such disturbed times.
Date: December 1, 1998
Creator: Korth, A.; Friedel, R.H.W.; Mouikis, C. & Fennell, J.F.
Partner: UNT Libraries Government Documents Department

New insights on geomagnetic storms from observations and modeling

Description: Understanding the response at Earth of the Sun's varying energy output and forecasting geomagnetic activity is of central interest to space science, since intense geomagnetic storms may cause severe damages on technological systems and affect communications. Episodes of southward (Bz<O) interplanetary magnetic field (IMF) which lead to disturbed geomagnetic conditions are associated either with coronal mass ejections (CMEs) and possess long and continuous negative IMF Bz excursions, or with high speed solar wind streams (HSS) whose geoeffectiveness is due to IMF Bz profiles fluctuating about zero with various amplitudes and duration. We show examples of ring current simulations during two geomagnetic storms representative of each interplanetary condition with our kinetic ring current atmosphere interactions model (RAM), and investigate the mechanisms responsible for trapping particles and for causing their loss. We find that periods of increased magnetospheric convection coinciding with enhancements of plasma sheet density are needed for strong ring current buildup. During the HSS-driven storm the convection potential is highly variable and causes small sporadic injections into the ring current. The long period of enhanced convection during the CME-driven storm causes a continuous ring current injection penetrating to lower L shells and stronger ring current buildup.
Date: January 1, 2009
Creator: Jordanova, Vania K
Partner: UNT Libraries Government Documents Department

Multi-satellite characterization of the large energetic electron flux increase at L = 4-7, in the five-day period following the March 24, 1991, solar energetic particle event

Description: Following the giant magnetic storm that started on March 24, 1991, and the immediately-preceding solar energetic particle (SEP) event, a dramatic increase in the flux of energetic electrons was observed to occur on several satellites (using Los Alamos instruments aboard two geosynchronous satellites and two GPS satellites, plus energetic electron data from the CRRES satellite) sampling the L=4-7 region of the magnetosphere. We find that: this flux buildup at the larger L-values (L--6-7) first appears near the magnetic equator and subsequently spreads to higher magnetic latitudes; the flux buildup near the magnetic equator peaks first at the higher L before it peaks at the lower L; analysis of the angular distribution of energetic electrons at geosynchronous orbit shows that the flux buildup begins first with the buildup of energetic electrons (>300 keV) moving perpendicular to the magnetic field.
Date: December 31, 1994
Creator: Ingraham, J. C.; Cayton, T. E. & Belian, R. D.
Partner: UNT Libraries Government Documents Department

Examining the specific entropy (density of adiabatic invariants) of the outer electron radiation belt

Description: Using temperature and number-density measurements of the energetic-electron population from multiple spacecraft in geosynchronous orbit, the specific entropy S = T/n{sup 2/3} of the outer electron radiation belt is calculated. Then 955,527 half-hour-long data intervals are statistically analyzed. Local-time and solar-cycle variations in S are examined. The median value of the specific entropy (2.8 x 10{sup 7} eVcm{sup 2}) is much larger than the specific entropy of other particle populations in and around the magnetosphere. The evolution of the specific entropy through high-speed-stream-driven geomagnetic storms and through magnetic-cloud-driven geomagnetic storms is studied using superposed-epoch analysis. For high-speed-stream-driven storms, systematic variations in the entropy associated with electron loss and gain and with radiation-belt heating are observed in the various storm phases. For magnetic-cloud-driven storms, multiple trigger choices for the data superpositions reveal the effects of interplanetary shock arrival, sheath driving, cloud driving, and recovery phase. The specific entropy S = T/n{sup 2/3} is algebraically expressed in terms of the first and second adiabatic invariants of the electrons: this allows a relativistic expression for S in terms of T and n to be derived. For the outer electron radiation belt at geosynchronous orbit, the relativistic corrections to the specific entropy expression are -15%.
Date: January 1, 2008
Creator: Borovsky, Joseph E & Denton, Michael H
Partner: UNT Libraries Government Documents Department

An analysis on the mid-latitude scintillation and coherence frequency bandwidth using transionospheric VHF signals

Description: An analysis was perfonned on the mid-latitude scintillation and coherence frequency bandwidth (Fcoh) using transionospheric VHF signal data. The data include 1062 events spanning from November 1997 to June 2002. Each event records FORTE satellite received VHF signals from LAPP located at Los Alamos, New Mexico. Fcohs were derived to study scintillation characteristics on diurnal and seasonal variations, as well as changes due to solar and geomagnetic activities. Comparisons to the VHFIUHF coherence frequency bandwidth studies previously reported at equatorial and mid-latitude regions are made using a 4th power frequency dependence relationship. Furthennore, a wideband ionospheric scintillation model, WBMOD, was used to estimate Fcohs and compared with our VHF Fcoh values. Our analysis indicates mid-latitude scintillation characteristics that are not previously revealed. At the VHF bottom frequency range (3035 MHz), distinguished smaller Fcohs are found in time period from sunset to midnight, in wann season from May to August, and in low solar activity years. The effects of geomagnetic storm activity on Fcoh are characterized by a sudden transition at a Kp index of 50-60. Comparisons with median Fcohs estimated from other studies validated our VHF Fcohs for daytime while an order of magnitude larger Fcohs are found for nighttime, implying a time-dependent issue in applying the 4th order power relationship. Furthermore, comparisons with WBMOD-estimated Fcohs indicated generally matched median scintillation level estimates while differences do exist for those events undergoing high geomagnetic stonn activity which may imply underestimates of scintillation level by the WBMOD in the mid-latitude regions.
Date: January 1, 2008
Creator: Juang, Zhen & Roussel-dupre, Robert
Partner: UNT Libraries Government Documents Department

Electric Utility Industry Experience with Geomagnetic Disturbances

Description: A geomagnetic disturbance (GMD) by its nature occurs globally and almost simultaneously. Severe geomagnetic storms cause problems for electric power systems. The vulnerability of electric power systems to such events has apparently increased during the last 10 to 20 years because power system transmission lines have become more interconnected and have increased in length and because power systems are now operated closer to their limits than in the past. In this report, the experience of electric utilities during geomagnetic storms is examined and analyzed. Measured data, effects on power system components, and power system impacts are considered. It has been found that electric power systems are susceptible to geomagnetically induced earth-surface potential gradients as small as a few (2 to 3) volts per kilometer, corresponding to a storm of K-6 intensity over an area of high earth resistivity. The causes and effects are reasonably well understood, but additional research is needed to develop a better understanding of solar-induced geomagnetic storms and the responses of power systems to these types of storms. A better understanding of geomagnetic storms and the power systems' responses to GMDs is needed so that mitigation measures can be implemented that will make power systems less susceptible to severe geomagnetic disturbances. A GMD caused by a large high-altitude nuclear detonation is similar in many ways to that of solar-induced geomagnetic storms except that a nuclear-caused disturbance would be much more intense with a far shorter duration.
Date: January 1, 1991
Creator: Barnes, P.R.
Partner: UNT Libraries Government Documents Department

Geophysical Institute. Biennial report, 1993-1994

Description: The 1993-1994 Geophysical Institute Biennial Report was published in November 1995 by the Geophysical Institute of the University of Alaska Fairbanks. It contains an overview of the Geophysical Institute, the Director`s Note, and research presentations concerning the following subjects: Scientific Predictions, Space Physics, Atmospheric Sciences, Snow, Ice and Permafrost, Tectonics and Sedimentation, Seismology, Volcanology, Remote Sensing, and other projects.
Date: January 1, 1996
Partner: UNT Libraries Government Documents Department

Energetic neutral atom imaging with the Polar CEPPAD/IPS instrument: Initial forward modeling results

Description: Although the primary function of the CEP-PAD/IPS instrument on Polar is the measurement of energetic ions in-situ, it has also proven to be a very capable Energetic neutral Atom (ENA) imager. Raw ENA images are currently being constructed on a routine basis with a temporal resolution of minutes during both active and quiet times. However, while analyses of these images by themselves provide much information on the spatial distribution and dynamics of the energetic ion population in the ring current, detailed modeling is required to extract the actual ion distributions. In this paper, the authors present the initial results of forward modeling an IPS ENA image obtained during a small geo-magnetic storm on June 9, 1997. The equatorial ion distribution inferred with this technique reproduces the expected large noon/midnight and dawn/dusk asymmetries. The limitations of the model are discussed and a number of modifications to the basic forward modeling technique are proposed which should significantly improve its performance in future studies.
Date: December 31, 1997
Creator: Henderson, M.G.; Reeves, G.D.; Moore, K.R.; Spence, H.E.; Jorgensen, A.M.; Fennell, J.F. et al.
Partner: UNT Libraries Government Documents Department

Particle Transport and Energization Associated with Disturbed Magnetospheric Events

Description: Energetic particle flux enhancement events observed by satellites during strongly disturbed events in the magnetosphere (e.g., substorms, storm sudden commencements, etc.) are studied by considering interaction of particles with Earthward propagating electromagnetic pulses of westward electric field and consistent magnetic field of localized radial and azimuthal extent in a background magnetic field. The energetic particle flux enhancement is mainly due to the betatron acceleration process: particles are swept by the Earthward propagating electric field pulses via the EXB drift toward the Earth to higher magnetic field locations and are energized because of magnetic moment conservation. The most energized particles are those which stay in the pulse for the longest time and are swept the longest radial distance toward the Earth. Assuming a constant propagating velocity of the pulse we obtain analytical solutions of particle orbits. We examine substorm energetic particle injection by computing the particle flux and comparing with geosynchronous satellite observations. Our results show that for pulse parameters leading to consistency with observed flux values, the bulk of the injected particles arrive from distances less than 9 R(subscript E), which is closer to the Earth than the values obtained by the previous model and is also closer to the distances obtained by the injection boundary model.
Date: November 1, 1999
Creator: Cheng, C.Z.; Johnson, J.R. & Zaharia, S.
Partner: UNT Libraries Government Documents Department

SOLAR WINDS

Description: It is suggested that corpuscular radiation is hydrodynamic expansion of the solar corona which is called solar wind. Arguments are presented for this expansion of the solar corona in terms of motion of the comet tail aurorae production, magnetic storms, and cosmic-ray effects on earth. The corona is taken to be isotherrnal out to an undefined distance (in multiples of the radius of the base of the corona) and from there it expands adiabatically until supersonic velocities are reached at infinity. The solar wind is considered to continue after five astronomical units on the spiralling solar magnetic field. Applications of the solar wind hypothesis to solar sailing are discussed. (C.J.G.)
Date: November 1, 1959
Creator: Parker, E.N.
Partner: UNT Libraries Government Documents Department

Slow-mode shocks in the earth's magnetosphere

Description: The locations and structure of slow-mode shocks in the earth's magnetosphere are reviewed. To date, such shocks have only been identified along the high latitude portions of the lobe-plasma sheet boundary of the geomagnetic tail. Although their intrinsic thickness is of the order of the upstream ion inertial length, they affect the internal state of a relatively much larger volume of surrounding plasma. In particular, they support a well-developed foreshock very similar to that observed upstream of the earth's bow shock, and a turbulent, strongly convecting downstream flow. They also figure importantly in the energy budget of geomagnetic substorms and produce effects which are closely analogous to much of the phenomenology known from solar observations to be associated with two-ribbon flares. 74 refs., 14 figs.
Date: January 1, 1987
Creator: Feldman, W.C.
Partner: UNT Libraries Government Documents Department

Impulsive ion acceleration in earth's outer magnetosphere

Description: Considerable observational evidence is found that ions are accelerated to high energies in the outer magnetosphere during geomagnetic disturbances. The acceleration often appears to be quite impulsive causing temporally brief (10's of seconds), very intense bursts of ions in the distant plasma sheet as well as in the near-tail region. These ion bursts extend in energy from 10's of keV to over 1 MeV and are closely associated with substorm expansive phase onsets. Although the very energetic ions are not of dominant importance for magnetotail plasma dynamics, they serve as an important tracer population. Their absolute intensity and brief temporal appearance bespeaks a strong and rapid acceleration process in the near-tail, very probably involving large induced electric fields substantially greater than those associated with cross-tail potential drops. Subsequent to their impulsive acceleration, these ions are injected into the outer trapping regions forming ion ''drift echo'' events, as well as streaming tailward away from their acceleration site in the near-earth plasma sheet. Most auroral ion acceleration processes occur (or are greatly enhanced) during the time that these global magnetospheric events are occurring in the magnetotail. A qualitative model relating energetic ion populations to near-tail magnetic reconnection at substorm onset followed by global redistribution is quite successful in explaining the primary observational features. Recent measurements of the elemental composition and charge-states have proven valuable for showing the source (solar wind or ionosphere) of the original plasma population from which the ions were accelerated.
Date: January 1, 1985
Creator: Baker, D.N. & Belian, R.D.
Partner: UNT Libraries Government Documents Department

Theory of magnetospheric hydromagnetic waves excited by energetic ring-current protons

Description: A general theoretical formulation, allowing finite ion Larmor radii, general magnetic field geometries and plasma equilibria, has been developed to investigate excitations of magnetohydrodynamic (MHD) Alfven waves within the earth's magnetosphere by the storm-time energetic ring-current protons. In particular, it is found that for adiabatically injected protons, various predicted instability properties are consistent with satellite observations. 8 refs.
Date: June 1, 1987
Creator: Chen, Liu & Hasegawa, Akira
Partner: UNT Libraries Government Documents Department

Magnetic field draping about coronal mass ejecta

Description: Fast coronal mass ejecta (CMEs) accelerate and deflect the slower moving solar wind plasma which piles up ahead of them as they propagate out through the heliosphere. This acceleration and deflection, in turn, causes the interplanetary magnetic field (IMF) imbedded in the upstream solar wind to drape about the ejecta. Draping should cause substantial out-of-the-ecliptic magnetic fields at some locations ahead of CMEs, and radial fields behind and along the flanks. At the Earth, draping can be an important factor in the generation of some magnetic storms and substorms, while in the outer heliosphere draping may produce very large magnetotail-like configurations, somewhat analogous to those observed behind Venus and comets. 17 refs.
Date: January 1, 1987
Creator: McComas, D.J. & Gosling, J.T.
Partner: UNT Libraries Government Documents Department

Particle and field signatures of substorms in the near magnetotail

Description: The near-earth magnetotail (10 less than or equal to r less than or equal to 20 R/sub E/) portion of the terrestrial magnetosphere is very likely the region in which magnetospheric substorms are initiated and it is in this location that substorm-related magnetic reconnection appears to occur. An observational advantage compared to other astrophysical regions is that the near magnetotail can be nearly continuously monitored by spacecraft that are relatively fixed in location. Observations of magnetic fields and plasma distribution functions in the neartail reveal a very regular and predictable sequence of variation in association with substorms. These data, considered in a global context, provide very strong evidence for the neutral line substorm model and, thus, for the regular occurrence of magnetic reconnection in the near-earth magnetotail during substorms.
Date: January 1, 1983
Creator: Baker, D.N.
Partner: UNT Libraries Government Documents Department

Real-time ISEE data system

Description: Prediction of geomagnetic substorms and storms would be of great scientific and commercial interest. A real-time ISEE data system directed toward this purpose is discussed in detail. Such a system may allow up to 60+ minutes advance warning of magnetospheric substorms and up to 30 minute warnings of geomagnetic storms (and other disturbances) induced by high-speed streams and solar flares. The proposed system utilizes existing capabilities of several agencies (NASA, NOAA, USAF), and thereby minimizes costs. This same concept may be applicable to data from other spacecraft, and other NASA centers; thus, each individual experimenter can receive quick-look data in real time at his or her base institution. 6 figures, 1 table.
Date: January 1, 1979
Creator: Tsurutani, B.T. & Baker, D.N.
Partner: UNT Libraries Government Documents Department

Statistical analyses in the study of solar wind-magnetosphere coupling

Description: Statistical analyses provide a valuable method for establishing initially the existence (or lack of existence) of a relationship between diverse data sets. Statistical methods also allow one to make quantitative assessments of the strengths of observed relationships. This paper reviews the essential techniques and underlying statistical bases for the use of correlative methods in solar wind-magnetosphere coupling studies. Techniques of visual correlation and time-lagged linear cross-correlation analysis are emphasized, but methods of multiple regression, superposed epoch analysis, and linear prediction filtering are also described briefly. The long history of correlation analysis in the area of solar wind-magnetosphere coupling is reviewed with the assessments organized according to data averaging time scales (minutes to years). It is concluded that these statistical methods can be very useful first steps, but that case studies and various advanced analysis methods should be employed to understand fully the average response of the magnetosphere to solar wind input. It is clear that many workers have not always recognized underlying assumptions of statistical methods and thus the significance of correlation results can be in doubt. Long-term averages (greater than or equal to 1 hour) can reveal gross relationships, but only when dealing with high-resolution data (1 to 10 min) can one reach conclusions pertinent to magnetospheric response time scales and substorm onset mechanisms.
Date: February 12, 1985
Creator: Baker, D.N.
Partner: UNT Libraries Government Documents Department

Implications of the 1100 UT March 22, 1979 CDAW 6 substorm event for the role of magnetic reconnection in the geomagnetic tail

Description: The event of March 22, 1979 has been the object of a concentrated study effort as a part of the Coordinated Data Analysis Workshop activity designated CDAW-6. Energetic electron and magnetic field measurements from a set of four satellites aligned from 6.6 to 13 R/sub E/ at the 0200 LT meridian at the time of the magnetospheric substorm event of 1100 UT are presented. These data are used to show that a magnetic X-line formed spontaneously in the vicinity of 7 R/sub E/ in response to a steady build-up of magnetic stress in the geomagnetic tail.
Date: January 1, 1983
Creator: Fritz, T.A.; Baker, D.N.; McPherron, R.L. & Lennartsson, W.
Partner: UNT Libraries Government Documents Department

Impact of quasi-dc currents on three-phase distribution transformer installations

Description: This report summarizes a series of tests designed to determine the response of quasi-dc currents on three-phase power distribution transformers for electric power systems. In general, if the dc injection is limited to the primary side of a step-down transformer, significant harmonic distortion is noted and an increase in the reactive power demand results. For dc injection on the secondary (load) side of the step-down transformer the harmonic content at the secondary side is quite high and saturation occurs with a relatively low level of dc injection; however, the reactive power demand is significantly lower. These tests produced no apparent damage to the transformers. Transformer damage is dependent on the duration of the dc excitation, the level of the excitation, and on thermal characteristics of the transfer. The transformer response time is found to be much shorter than seen in power transformer tests at lower dc injection levels. This shorter response time suggests that the response time is strongly dependent on the injected current levels, and that higher levels of dc injection for shorter durations could produce very high reactive power demands and harmonic distortion within a few tenths of a second. The added reactive power load could result in the blowing of fuses on the primary side of the transformer for even moderate dc injection levels, and neutral currents are quite large under even low-level dc injection. This smoking neutral'' results in high-level harmonic injection into equipment via the neutral and in possible equipment failure.
Date: June 1, 1992
Creator: McConnell, B.W.; Barnes, P.R. (Oak Ridge National Lab., TN (United States)); Tesche, F.M. (Tesche (F.M.), Dallas, TX (United States)) & Schafer, D.A. (Mission Research Corp., Albuquerque, NM (United States))
Partner: UNT Libraries Government Documents Department

Mitigation of magnetohydrodynamic electromagnetic pulse (MHD-EMP) effects from commerical electric power systems

Description: A large nuclear detonation at altitudes of several hundred kilometers above the earth distorts the earth's magnetic field and produces a strong magnetohydrodynamic electromagnetic pulse (MHD-EMP). This can adversely affect electrical power systems. In this report, the effects of this nuclear environment on critical facilities connected to the commercial power system are considered. Methods of mitigating the MHD-EMP impacts are investigated, and recommended protection schemes are presented. Guidelines for testing facilities to determine the effects of MHD-EMP and to validate the mitigation methods also are discussed.
Date: March 1, 1992
Creator: Barnes, P.R. (Oak Ridge National Lab., TN (United States)); Tesche, F.M. (Tesche (F.M.), Dallas, TX (United States)) & Vance, E.F. (Vance (E.F.), Fort Worth, TX (United States))
Partner: UNT Libraries Government Documents Department