Publications involving OpenGGCM in (roughly) chronological ordering:
The importance of small scale processes in global MHD simulations: Some numerical experiments --- Raeder, J., J. Berchem, and M. Ashour-Abdalla --- 1996
Abstract: We have used our global MHD model to asses the importance of small scale processes for magnetospheric dynamics. The comparison of two simulation runs, on with, and one without anomalous resistivity, and with otherwise identical parameters, shows that a substorm only develops when anomalous resistivity is present. A similar comparison of a simulation run with a self-consistent ionospheric conductance model and a run in which the ionospheric conductance was increased, shows that increased ionospheric conductance can likewise prevent the occurrence of a substorm. We conclude that the proper parameterization of these small scale processes is importance for global modeling of the magnetosphere. Our results also show that substorm models must account for localized processes, like the occurrence of anomalous resistivity, as well as for the response of the ionosphere.
Citation: Raeder, J., J. Berchem, and M. Ashour-Abdalla, The importance of small scale processes in global MHD simulations: Some numerical experiments, in The Physics of Space Plasmas, editor(s): T. Chang, and J.R. Jasperse, 14, 403, Publisher: MIT Center for Theoretical Geo/Cosmo Plasma Physics, Cambridge MA
Source (local): Raeder_Berchem_AshourAbdalla_Small_Scale_Processes.pdf
In BibTex as: Raeder1996a
Boundary layer formation in the magnetotail: Geotail observations and comparisons with a global MHD simulation --- Raeder, J., J. Berchem, M. Ashour-Abdalla, L. A. Frank, W. R. Paterson, K. L. Ackerson, S. Kokubun, T. Yamamoto, and J. A. Slavin --- 1997
Abstract: We present Geotail plasma and field observations from the middle magnetotail near XGSE =−46 RE for the time period 1400 to 1800 UT on December 14, 1994. During that period, the Wind satellite monitored the solar wind plasma and interplanetary magnetic field (IMF) upstream of the bow shock. The IMF was northward and the plasma parameters near average. Geotail observed slow tailward flows and a northward field. The plasma and field parameters indicate that Geotail is either in the plasma sheet or in a boundary layer. We used the Wind solar wind plasma and IMF data as input for a global simulation of that time interval. Comparison of the simulation results with the observational data show very good overall agreement of the magnitudes of the plasma and field parameters. In particular, the simulation reproduces the slow tailward flows and northward field found at Geotail. Small scale temporal variations are less well reproduced. The simulation shows the formation of a broad boundary layer (which we call tail flank boundary layer, TFBL) that consists of closed flux which formed by magnetic reconnection of IMF and lobe field lines. The simulation results indicate that Geotail is located very close to the TFBL and may have entered the TFBL proper. We show that the TFBL plays an important role in energy transport from the solar wind into the magnetosphere during northward IMF conditions.
Citation: Raeder, J., J. Berchem, M. Ashour-Abdalla, L. A. Frank, W. R. Paterson, K. L. Ackerson, S. Kokubun, T. Yamamoto, and J. A. Slavin, Boundary layer formation in the magnetotail: Geotail observations and comparisons with a global MHD simulation, Geophysical Research Letters, 24, 951, 1997
Source: https://doi.org/10.1029/97GL00218
In BibTex as: Raeder1997a
The Geospace Environment Modeling Grand Challenge: Results from a Global Geospace Circulation Model --- Raeder, J., J. Berchem, and M. Ashour-Abdalla --- 1998
Abstract: We have used our Global Geospace Circulation Model (GGCM) to simulate two time intervals that were proposed as the Geospace Environment Modeling (GEM) Grand Challenge for modelers to investigate to what extent and accuracy models can predict the ionosphere's response to the solar wind and interplanetary magnetic field. In this paper we present comparisons of our GGCM with the comprehensive experimental study by Lyons [this issue] (which provided synoptic maps of the polar cap electrodynamics and particle precipitation) for the two time intervals, January 27, 1992, 1325–1715 UT and 1730–1930 UT. We find a very good agreement between the potential patterns predicted by our model and those obtained by the assimilative mapping of ionospheric electrodynamics (AMIE) procedure. We also find that the separatrix and cusp locations predicted by our model generally compare well with those obtained from particle precipitation data. The soft electron zone of ionospheric precipitation, as defined by Lyons, lies almost entirely in the region for which our model predicts open field lines. However, the model predicts cross polar cap potential drops that are roughly a factor of 2 larger than those predicted by AMIE.
Citation: Raeder, J., J. Berchem, and M. Ashour-Abdalla, The Geospace Environment Modeling Grand Challenge: Results from a Global Geospace Circulation Model, J. Geophys. Res., 103, 14787, 1998
Source: https://doi.org/10.1029/98JA00014
In BibTex as: Raeder1998a
Determination of Particle Sources for a Geotail Distribution Function Observed on May 23, 1995 --- Ashour-Abdalla, M., M. El-Alaoui, V. Peroomian, J. Raeder, R.L. Richard, R.J. Walker, L.M. Zelenyi, L.A. Frank, W.R. Paterson, J.M. Bosqued, R.P. Lepping, K. Ogilvie, S. Kokubun, and T. Yamamoto --- 1998
Citation: Ahour-Abdalla, M., M. El-Alaoui, V. Peroomian, J. Raeder, R.L. Richard, R.J. Walker, L.M. Zelenyi, L.A. Frank, W.R. Paterson, J.M. Bosqued, R.P. Lepping, K. Ogilvie, S. Kokubun, and T. Yamamoto, Determination of Particle Sources for a Geotail Distribution Function Observed on May 23, 1995, in: Geospace Mass Energy Flow: Results from the International Solar-Terrestrial Physics Program, Geophysical Monograph , 104, 1998
Source: https://doi.org/10.1029/GM104p0297
In BibTex as: Ashour-Abdalla1998a
Modeling Magnetotail Ion Distributions with Global Magnetohydrodynamic and Ion Trajectory Calculations --- El-Alaoui, M, M. Ashour-Abdalla, J. Raeder, V. Peroomian, L.A. Frank, W.R. Paterson, and J.M. Bosqued --- 1998
Citation: El-Alaoui, M, M. Ashour-Abdalla, J. Raeder, V. Peroomian, L.A. Frank, W.R. Paterson, and J.M. Bosqued, Modeling Magnetotail Ion Distributions with Global Magnetohydrodynamic and Ion Trajectory Calculations, in: Geospace Mass and Energy Flow: Results from the International Solar-Terrestrial Physics Program, Geophysical Monograph, 104, Publisher: AGU, 1998
Source: https://doi.org/10.1029/GM104p0291
In BibTex as: El-Alaoui1998a
Magnetotail Structure and its Internal Particle Dynamics During Northward IMF --- M. Ashour-Abdalla, J. Raeder, M. El-Alaoui, and V. Peroomian --- 1998
Citation: M. Ashour-Abdalla, J. Raeder, M. El-Alaoui, and V. Peroomian, Magnetotail Structure and its Internal Particle Dynamics During Northward IMF, in: New Perspectives on the Earths Magnetotail, Geophysical Monograph, 105, 1998
Source: https://doi.org/10.1029/GM105p0077
In BibTex as: Ashour-Abdalla1998b
Global MHD Simulations of the Substorm Current Wedge and Diploarization --- Raeder, J., and R. L. McPherron --- 1998
Abstract: This paper presents results from global MHD simulations showing the evolution of the plasma and field in the near-Earth tail during the substorm phases. The late growth phase is characterized by pronounced thinning of the plasma sheet and stretching of the field in the region between approximately -6 $R_{E}$ to -30 $R_{E}$. A pre-existing X-line moves tailward to beyond -50 $R_{E}$. Close to onset, a new X-line forms near -18 $R_{E}$ in the midnight sector. Earthward flows emanating from this X-line dipolarize the near-Earth filed, leading to a reduction of the cross-tail current in the midnight sector, but not elsewhere. The magnetic shear between the dipolarized field near midnight and the stretched field elsewhere is equivalent to currents flowing through the ionosphere in a region 1 sense, and so forming the current wedge. Later in the expansion phase, the dipolarization spreads in local time at a rate of about 0.3 hours MLT per minute. A strong electric field and a rapid increase of the plasma pressure is associated with the dipolarization. Near midnight the diploarization appears to occur at all distance between 6.6 and 13 $R_{E}$ at the same time within the resolution (+/-2 min) of our model. However, the model results indicate that dipolarization starts \emph{before} ground onset in the pre-midnight sector and propagates both earthward and eastward. Thus, dipolarization may be much more complex than simple earthward/tailward and/or azimuthal expansion.
Citation: Raeder, J., and R. L. McPherron, GLOBAL MHD SIMULATIONS OF THE SUBSTORM CURRENT WEDGE AND DIPOLARIZATION, in: Substorms-4, editor(s): S. Kokubun and Y. Kamide, Publisher: Kluwer Academic Publishers Dordrecht, 343, 1998
Source (local): Raeder_McPherron_Global_MHD_Sim.pdf
In BibTex as: Raeder1998b
Using Global Simulations of the Magnetosphere for Multi-Satellite Mission Planning and Data Analysis --- Raeder, J., and V. Angelopoulos --- 1998
Abstract: We use global simulations of Earth's magnetosphere to asses the expected scientific return from a multi satellite mission in the magnetosphere. We examine 4 different scenarios with 20, 40, 80, 160 satellites, respectively. The satellite orbits are randomized with perigee distance ranging from 2 to 5 $R_{E}$, apogee distance between 10 and 50 $R_{E}$, and within +/- 5 $R_{E}$ of the geocentric solar ecliptic (GSE) equator. For each of these satellite configurations we examine the expected observations during a typical substorm by using time traces obtained from a global simulation at the satellite positions. The 160 satellite configuration yields sufficient information to distinguish between different substorm models without any temporal/spatial ambiguities. A 80 satellite configuration still provides sufficient information for this task, however for fewer events with good satellite conjunctions and with less statistical certainty. For constellations with 40 satellites or less time - space ambiguities are likely to remain in the observation. However, any multi satellite constellation would be a quantum leap in magnetospheric research because of the unprecedented coverage of other regions, because it would enable new measurement techniques that are unique to multi satellite missions, and because it would enable the use of data assimilation techniques in global models for the first time.
Citation: Raeder, J., and V. Angelopoulos, Using Global Simulations of the Magnetosphere for Multi-Satellite Mission Planning and Data Analysis, in: Science Closure and Enabling Technologies for Constellation Class Missions, editor(s): V. Angelopoulos and P. Panetta, 78, Publisher: University of California Berkeley, 1998
Source (local): Raeder_Angelopoulos_Using_Global_Simulations.pdf
In BibTex as: Raeder1998c
Modeling the Magnetosphere for Northward Interplanetary Magnetic Field: Effects of Electrical Resistivity --- Raeder, J. --- 1999
Abstract: We develop a simple analytic model and use global simulations of Earth's magnetosphere to investigate the effects of electrical resistivity on the topology of the magnetosphere for northward interplanetary magnetic field (IMF). We find that for low resistivity values (≲104 Ω m) the magnetosphere remains open after 6 hours of northward IMF. For larger values (≳2×105 Ω m) the magnetic flux of the tail lobes decreases rapidly on the timescale of ∼1 hour. In this case the tail becomes closed, tadpole-shaped, steady state, and of finite length. The tail length decreases with increasing resistivity and becomes as short as about 50 RE for a resistivity value of 106 Ω m. Reconnection between IMF and lobe field lines occurs in all cases and is not significantly affected by the resistivity. However, large values of the resistivity annihilate lobe flux and break the frozen-in condition for closed tail flux tubes, leading to a decoupling of the flux tube motion from plasma convection. These effects make the development of a steady, closed tail of finite length possible. Because resistivity values larger than 102 Ω m are unrealistic for the quiet time tail, we conclude that the magnetosphere is unlikely to ever close and that models which predict the rapid closure and a steady, finite length tail are possibly in error due to numerical resistivity.
Citation: Raeder, J., Modeling the Magnetosphere for Northward Interplanetary Magnetic Field: Effects of Electrical Resistivity, Journal of Geophysical Research, 104, 17357-17367, 1999
Source: https://doi.org/10.1029/1999JA900159
In BibTex as: Raeder1999a
Interball tail probe observations and global simulations --- Raeder, J., O. Vaisberg, V. Smirnov, L. Avanov --- 2000
Abstract: We present Interball Tail Probe observations from the high latitude mid-tail magnetopause which provide evidence of reconnection between the interplanetary magnetic field (IMF) and lobe field lines during a 6 h interval of stable northward and dawnward IMF on October 19, 1995. Results from a global magnetohydrodynamic simulation for this interval compare well with the Interball observations. With the simulations, we provide an extended global view of this event which gives us insight into the reconnection and convection dynamics of the magnetosphere. We find that reconnection occurs in a region of limited spatial extent near the terminator and where the IMF and the lobe field are anti-parallel. Reconnected IMF field lines drape over the dayside magnetosphere, convect along the flanks into the nightside, and enter the magnetotail through a small entry window that is located in the flank opposite to the reconnection site. Ionospheric convection is consistent with previous observations under similar IMF conditions and exhibits a two cell pattern with a dominant lobe cell over the pole. The magnetic mapping between the ionosphere and the lobe boundary is characterized by two singularities: the narrow entry window in the tail maps to a 6 h wide section of the ionospheric lobe cell. A singular mapping line cuts the lobe cell open and maps to almost the entire tail magnetopause. By this singularity the magnetosphere avoids having a stagnation point, i.e., the lobe cell center maps to a tailward convecting field line. The existence of singularities in the magnetic mapping between the ionosphere and the tail has important implications for the study of tail–ionosphere coupling via empirical magnetic field models. Because the lobe–IMF reconnection cuts away old lobe flux and replaces it with flux tubes of magnetosheath origin, solar wind plasma enters the lobes in a process that is similar to the one that operates during southward IMF.
Citation: Raeder, J., O. Vaisberg, V. Smirnov, L. Avanov, Reconnection driven lobe convection: Interball tail probe observations and global simulations, Journal of Atmospheric and Solar-Terrestrial Physics, 62, 833, 2000
Source: https://doi.org/10.1016/S1364-6826(00)00041-9
In BibTex as: Raeder2000a
The origin of the near-Earth plasma population during a substorm on November 24, 1996 --- Ashour-Abdalla, M., M. El-Alaoui, V. Peroomian, R.J. Walker, J. Raeder, L.A. Frank, and W.R. Paterson --- 2000
Abstract: We investigate the origins and the transport of ions observed in the near-Earth plasma sheet during the growth and expansion phases of a magnetospheric substorm that occurred on November 24, 1996. Ions observed at Geotail were traced backward in time in time-dependent magnetic and electric fields to determine their origins and the acceleration mechanisms responsible for their energization. Results from this investigation indicate that during the growth phase of the substorm, most of the ions reaching Geotail had origins in the low-latitude boundary layer and had already entered the magnetosphere when the growth phase began. Late in the growth phase and in the expansion phase a higher proportion of the ions reaching Geotail had their origin in the plasma mantle. Indeed, during the expansion phase, more than 90\% of the ions seen by Geotail were from the mantle. The ions were accelerated enroute to the spacecraft; however, most of the ions' energy gain was achieved by nonadiabatic acceleration while crossing the equatorial current sheet just prior to their detection by Geotail. In general, the plasma mantle from both southern and northern hemispheres supplied nonadiabatic ions to Geotail, whereas the LLBL supplied mostly adiabatic ions to the distributions measured by the spacecraft. Distribution functions computed at the ion sources indicate that ionospheric ions reaching Geotail during the expansion phase were significantly heated. Plasma mantle source distributions indicated the presence of a high-latitude reconnection region that allowed ion entry into the magnetosphere when the interplanetary magnetic field was northward. These ions reached Geotail during the expansion phase. Ions from the traditional plasma mantle had access to the spacecraft throughout the substorm.
Citation: Ashour-Abdalla, M., M. El-Alaoui, V. Peroomian, R.J. Walker, J. Raeder, L.A. Frank, and W.R. Paterson, The origin of the near-Earth plasma population during a substorm on November 24, 1996, J. Geophys. Res., 105, 2589, 2000
Source: https://doi.org/10.1029/1999JA900389
In BibTex as: Ashour-Abdalla2000a
Geomagnetic Storm Simulation With a Coupled Magnetosphere-Ionosphere-Thermosphere Model --- Raeder, J., Y. Wang, and T. Fuller-Rowell --- 2001
Citation: Raeder, J., Y. Wang, and T. Fuller-Rowell, Geomagnetic Storm Simulation With a Coupled Magnetosphere-Ionosphere-Thermosphere Model, in: Space Weather: Progress and Challenges in Research and Applications, Geophysical Monograph 125, in: 377-384, editor(s): P. Song, H. J. Singer, and G. Siscoe. Publisher: AGU, Washington D.C., 2001
Source: https://doi.org/10.1029/GM125p0377
In BibTex as: Raeder2001a
Global Simulation of Magnetospheric Space Weather Effects of the Bastille Day Storm --- Raeder, J., Y. Wang, T. Fuller-Rowell, and H. J. Singer --- 2001
Abstract: We present results from a global simulation of the interaction of the solar wind with Earth's magnetosphere, ionosphere, and thermosphere for the Bastille Day geomagnetic storm and compare the results with data. We find that during this event the magnetosphere becomes extremely compressed and eroded, causing 3 geosynchronous GOES satellites to enter the magnetosheath for an extended time period. At its extreme, the magnetopause moves at local noon as close as 4.9 $R_{E}$ to Earth which is interpreted as the consequence of the combined action of enhanced dynamic pressure and strong dayside reconnection due to the strong southward interplanetary magnetic field component $B_{z}$, which at one time reaches a value of −60 nT. The lobes bulge sunward and shield the dayside reconnection region, thereby limiting the reconnection rate and thus the cross polar cap potential. Modeled ground magnetic perturbations are compared with data from 37 sub-auroral, auroral, and polar cap magnetometer stations. While the model can not yet predict the perturbations and fluctuations at individual ground stations, its predictions of the fluctuation spectrum in the 0–3 mHz range for the sub-auroral and high-latitude regions are remarkably good. However, at auroral latitudes (63° to 70° magnetic latitude) the predicted fluctuations are slightly too high.
Citation: Raeder, J., Y. Wang, T. Fuller-Rowell, and H. J. Singer, Global Simulation of Magnetospheric Space Weather Effects of the Bastille Day Storm, Solar Physics, 204, 325, 2001
Source: https://doi.org/10.1023/A:1014228230714
In BibTex as: Raeder2001b
Polar cusp and vicinity under strongly northward IMF on April 11, 1997: Observations and MHD simulations --- Le, G., J. Raeder, C.T. Russell, G. Lu, S.M. Petrinec, an F.S. Mozer --- 2001
Abstract: We present a correlative case study of the solar wind interaction with the magnetosphere using in situ observations of the polar cusp and surrounding regions, ground-based and low-altitude spacecraft polar cap observations, and global MHD simulations during an extended period of strongly northward interplanetary magnetic field (IMF) on April 11, 1997. Within this extended period of strongly northward IMF, the Polar spacecraft entered a region with magnetosheath-like plasma and field lines above the polar cusp. Data from multiple instruments on Polar showed that the observed signatures can be interpreted as Polar entering the reconnection layer and crossing the current layer associated with it. The magnetosheath-like field lines encountered by Polar have just reconnected poleward of the polar cusp in the north. The reversed ionospheric convection patterns derived from the assimilative mapping of ionospheric electrodynamics (AME) technique show the reversed convection over the polar cap due to high-latitude reconnection throughout the whole interval. MHD simulations were performed using solar wind parameters observed by Wind, supporting the cusp reconnection interpretation.
Citation: Le, G., J. Raeder, C.T. Russell, G. Lu, S.M. Petrinec, an F.S. Mozer, Polar cusp and vicinity under strongly northward IMF on April 11, 1997: Observations and MHD simulations, J. Geophys. Res., 106, 21083, 2001
Source: https://doi.org/10.1029/2000JA900091
In BibTex as: Le2001a
