Magnetospheric configuration and dynamics of Saturn's magnetosphere: A global MHD simulation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95292/1/jgra21912.pd

A Parallel Adaptive 3D MHD Scheme for Modeling Coronal and Solar Wind Plasma Flows

A parallel adaptive mesh refinement (AMR) scheme is described for solving the governing equations of ideal magnetohydrodynamics (MHD) in three space dimensions. This solution algorithm makes use of modern finite-volume numerical methodology to provide a combination of high solution accuracy and computational robustness. Efficient and scalable implementations of the method have been developed for massively parallel computer architectures and high performance achieved. Numerical results are discussed for a simplified model of the initiation and evolution of coronal mass ejections (CMEs) in the inner heliosphere. The results demonstrate the potential of this numerical tool for enhancing our understanding of coronal and solar wind plasma processes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43790/1/11214_2004_Article_234016.pd

Dust–Gas Interrelations In Comets: Observations And Theory

The development of the expanding atmospherefrom the evaporating cometary nucleus has traditionallyfocused on observing and modeling the separatedevelopment of two distinct components, gas and dust,which are coupled dynamically with one another atdistances out to a few tens of cometary radii. In the lastdecade or so, however, direct evidence from observationsand suggestions from theory suggest that the dusty-gascoma is a tightly coupled system where material is transferredbetween the solid and gaseous phase as an importantintegral part of the basic development of the coma.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43256/1/11038_2004_Article_239224.pd

Probing the Edge of the Solar System: Formation of an Unstable Jet-Sheet

The Voyager spacecraft is now approaching the edge of the solar system. Near the boundary between the solar system and the interstellar medium we find that an unstable ``jet-sheet'' forms. The jet-sheet oscillates up and down due to a velocity shear instability. This result is due to a novel application of a state-of-art 3D Magnetohydrodynamic (MHD) code with a highly refined grid. We assume as a first approximation that the solar magnetic and rotation axes are aligned. The effect of a tilt of the magnetic axis with respect to the rotation axis remains to be seen. We include in the model self-consistently magnetic field effects in the interaction between the solar and interstellar winds. Previous studies of this interaction had poorer spatial resolution and did not include the solar magnetic field. This instability can affect the entry of energetic particles into the solar system and the intermixing of solar and interstellar material. The same effect found here is predicted for the interaction of rotating magnetized stars possessing supersonic winds and moving with respect to the interstellar medium, such as O stars.Comment: 9 pages, 4 figures, accepted for publication in ApJ

MHD Simulation of Comets: The Plasma Environment of Comet Hale–Bopp

MHD simulation results of the interaction of the expanding atmosphere of comet Hale-Bopp with the magnetized solar wind are presented. At the upstream boundary a supersonic and superalfvénic solar wind enters into the simulation box 25 million km upstream of the nucleus.The solar wind is continuously mass loaded with cometaryions originating from the nucleus. The effects of photoionization, recombination andion-neutral frictional drag are taken into account in the model.The governing equations are solved on an adaptively refined unstructured Cartesian grid using our MUSCL-type upwind numerical technique, MAUS-MHD(Multiscale Adaptive Upwind Scheme for MHD). The combination of the adaptive refinement with the MUSCL-scheme allows the entire cometary atmosphere to be modeled, while still resolving both the shock and the diamagnetic cavity of the comet.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43255/1/11038_2004_Article_239216.pd

3D multi‐fluid MHD studies of the solar wind interaction with Mars

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95115/1/grl13388.pd

A Three-dimensional Model of the Solar Wind Incorporating Solar Magnetogram Observations

We present a new compressible MHD model for simulating the three-dimensional structure of the solar wind under steady state conditions. The initial potential magnetic field is reconstructed throughout the computational volume using the source surface method, in which the necessary boundary conditions for the field are provided by solar magnetogram data. The solar wind in our simulations is powered by the energy interchange between the plasma and large-scale MHD turbulence, assuming that the additional energy is stored in the "turbulent" internal degrees of freedom. In order to reproduce the observed bimodal structure of the solar wind, the thermodynamic quantities for the initial state are varied with the heliographic latitude and longitude depending on the strength of the radial magnetic field

Two‐species, 3D, MHD simulation of Europa's interaction with Jupiter's magnetosphere

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95391/1/grl12120.pd

Effect of multiple substorms on the buildup of the ring current

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95361/1/jgra17662.pd

An Adaptively Refined Cartesian Mesh Solver for the Euler Equations

A method for adaptive refinement of a Cartesian mesh for the solution of the steady Euler equations is presented. The algorithm creates an initial uniform mesh and cuts the body out of that mesh. The mesh is then refined based on body curvature. Next, the solution is converged to a steady state using a linear reconstruction and Roe's approximate Riemann solver. Solution-adaptive refinement of the mesh is then applied to resolve high-gradient regions of the flow. The numerical results presented show the flexibility of this approach and the accuracy attainable by solution-based refinement.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31037/1/0000714.pd