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The current perturbation associated with magnetic reconnection has been measured in the Madison Symmetric Torus (MST). A reversed field pinch plasma configuration such as MST normally exhibits strong magnetic field fluctuations due to tearing modes. Large amplitude, highly spatially localized perturbations in the parallel current density are expected to occur in the region of the reconnection. One such region, the reversal surface, is in the plasma edge. This region was accessed using a pair of insertable probes, each with Rogowskii coils and magnetic coils. The current perturbation's radial structure is broad, comparable to the expected island width, rather than highly localized. The magnetic fluctuation driven radial charge flux due to these perturbations was also measured. This charge flux is proportional to the flux surface average of the product of the parallel current density perturbation and the radial magnetic field perturbation. The measured charge flux, considered as a difference between ion and electron fluxes, is small compared to the total particle flux.

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Solar flares, the reconnection-mediated release of magnetic energy stored in the coronal magnetic field, are physical phenomena of great interest in and of themselves, as well as for their geomagnetic consequences. In addition, according to a conjecture put forth a little over a decade by E.N. Parker, a population of very common but very small flares (the so-called nanoflares) might be responsible for coronal heating. In this talk I will first briefly review the coronal heating problem and Parker's conjecture. I will then discuss a model related to Parker's conjecture, in which flares take the form of an avalanche of small reconnection events in a complex stressed magnetic field driven to a state of self-organized criticality.

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Recent initiatives in space physics have emphasized understanding of solar disturbances and the quantitative prediction of resultant magnetospheric and ionospheric phenomena. These initiatives go under the name of `space weather'. Such quantitative predictions are of practical importance but also test of our understanding of the mechanisms by which the Sun influences the Earth. Solar activity in the form of solar flares, coronal mass injections (CME), and recurrent high speed streams influence Earth's space weather by increasing ionization in the ionosphere and by producing magnetic storms and their associated electrical currents, energetic charged particle injections, and aurora. Of increasing concern as mankind relies more on satellite systems are energetic particles, which can lead to satellite failure through radiation damage. In particular the MeV electrons, also known as `killer electrons', have a deleterious impact on satellite subsystems through deep dielectric discharging. Of special concern is the radiation environment at geostationary orbit where the largest number of satellites is located.

Here I report on a new method of predicting MeV electron fluxes at geostationary orbit 1-2 days in advance using only solar wind measurements. Using this method we have achieved a prediction efficiency of 0.82 and a linear correlation of 0.84 for the two years 1995 and 1996. Using the same model parameters based on the years 1995-1996, the prediction efficiency and the linear correlation for the five year period 1995-1999 are 0.61 and 0.77, respectively. The model is based on the standard radial diffusion equation, which is solved by setting the phase space density larger at the outer boundary than the inner boundary and by making the diffusion coefficient a function of solar wind velocity and interplanetary magnetic field. This model also provides a physical explanation for some observed features of the correlation between the solar wind and the electron flux.

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Non-neutral plasmas (e.g. pure-electron plasmas) confined in simple cylindrical traps provide excellent laboratory systems for the study of fluid dynamics and basic plasma transport processes. One such transport process is the viscous transport of particles and angular momentum across magnetic field lines. This type of transport brings about the confined thermal equilibrium state of rigid rotation and nearly uniform density. We have measured the coefficient of viscosity in pure-electron plasmas and find it to be as much as 8 orders of magnitude larger than what is predicted by Boltzmann collisional theory. The enhanced viscosity is due to long range "ExB drift collisions" where particles interact over distances on the order of the Debye length. (Here the Debye length is much larger than the cyclotron radius.) In this talk I will discuss these viscous transport measurements and their implications. In addition, I will provide a partial overview of the experimental and theoretical work done by the Non-neutral plasma group at U.C. San Diego.

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The physics of kinetic electrons and electromagnetic fluctuations are key challenges in microturbulence simulation research. Recently, we have made progress in this area by developing a drift-kinetic electron model using both the split-weight scheme and the canonical parallel momemtum formulation of gyrokinetics in a fully nonlinear three-dimensional toroidal field-line-following simulation. This model includes magnetic field perturbations perpendicular to the equilibrium magnetic field. Numerical issues arising from the resolution of the magnetic skin depth currently limit these simulations to small beta and progress in this area will be reported. A complementary hybrid simulation with fully gyrokinetic ions and a zero-inertia electron fluid has been developed as well. The electron fluid equations are derived from moments of the drift kinetic equation and a predictor-corrector scheme for the fluid-hybrid model has been implemented in three-dimensional toroidal field-line-following geometry. This is a much simpler electron model and works well at high beta. We are currently using both models to study the effects of electron dynamics on turbulence, including particle transport (which is zero in simulations using adiabatic response), kinetic Alfven modes and modification to zonal flows due to kinetic electrons and the generation of zonal fields through including parallel vector potential. Both hybrid and the fully kinetic simulations have been carefully benchmarked with linear theory in the slab limit. Simulation results for turbulence with both trapped-electron drive and ion-temperature-gradient drive will be presented. We will report results including the fluctuation spectra and transport levels (particle and energy) for both the ions and electrons for core H-mode plasma parameters.

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The National Transport Code Collaboration seeks to develop a code for studying anomalous transport in toroidally confined plasma. Much as experimentalists take diagnositics to facilities to study new phenomena experimentally, the NTCC Demonstration Code acts as a computational facility for new models for transport. Theorists must provide their code in the form of an object satisfying certain interface constraints. Having done so, they are in an environment where they may, on-line, check their theory against experiment and run their models with a web-invocable, graphical user interface. The next IAEA meeting will showcase results from the NTCC Demonstration Code.

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The Department of Pediatrics at the University of Colorado School of Medicine is developing a bank of video cases that correspond to the Pediatric National Curriculum. The cases are used in a WWW/CD-ROM hybrid program with "virtual" Problem-Based Learning (PBL) groups that conduct computer-mediated case discussions between a faculty mentor and students at multiple clinical sites. To the degree possible, our cases simulate a real encounter by using computer-based digital video rather than text, forcing the student to glean the information from the patient encounter and develop the visual recognition skills that are important in pediatric medicine. Unlike most adult patients that can verbally provide a history, pediatric patients very often cannot. Physicians must recognize visual and auditory cues to accurately diagnose a child. Digital video cases also afford the opportunity to model appropriate professional behavior and communication skills. These opportunities are especially important for difficult situations in which the physician needs effective communication skills. Students are often not allowed in some of those interviews and when they are included the variability of the modeling is problematic. Instructional strategies integrate group work, problem solving, and mentoring to support this teaching method. Collaborative learning across the Internet, combined with digital video cases has the potential to have a tremendous impact not only on medical education, but also on distance learning in general.

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The invention of the ion trap has led to impressive technological advances in physical measurements as well as the discovery of new states of matter. The motion of ions in the axisymmetric Paul trap has been successfully described by a classical Hamiltonian model, in which the ions move under the combined influence of the focusing RF quadrupole field and their mutual Coulomb repulsion. However, most current experiments are carried out in an asymmetric mode, in which the time-averaged "pseudopotential" is a triaxial ellipsoid. Critical points of this potential yield equilibria of ion "crystals", which "melt" to form "clouds". Chaotic motion can lead to enhanced RF heating and loss of ions. We present a classical description of one and two-ion dynamics in an elliptic trap. Stability boundaries for single ion motion are shown to decreased rapidly with increasing asymmetry. The two-ion motion takes place in a fully three-dimensional pseudopotential possessing three isolated critical points known as Morse saddles. Stability is lost when a pair of critical points change type. The results show that global confinement can prevail in the presence of unstable local equilibria. Chaotic motion is studied using four-dimensional surfaces of section.

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