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Paper: Adaptive, Lagrangian, Meshless Magnetohydrodynamics with Phurbas
Volume: 474, Numerical Modeling of Space Plasma Flows (ASTRONUM2012)
Page: 265
Authors: McNally, C. P.; Maron, J. L.; Mac Low, M.-M.
Abstract: Phurbas implements an a meshless algorithm for magnetohydrodynamics with features that are particularly useful for disks. The fields are represented on an unstructured set of sample particles. Local, third order, least squares, polynomial interpolations are calculated form the values of neighbouring particles to obtain spatial derivatives of fields. Particle values and positions are advanced in time with a second order predictor corrector scheme. As the particles are not connected by a mesh and simply trace field values at a point, new particles can be added and redundant ones deleted as needed to maintain a given spatial resolution. This allows full adaptivity in the sense that the target spatial resolution can be a function of time and space. The scheme is stabilised with a set of dynamics artificial viscosity fields. The particles move in a Lagrangian manner (with the fluid) so that the time step is not limited by the bulk motion of the fluid, and each particle evolves on an individually determined time step. We present the Phurbas algorithm and a demonstration of a global magnetorotational instability driven turbulent disk model, which includes the use of zoom-in high resolution regions comoving with the flow.
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