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The energy production through thermo-nuclear fusion requires the confinement of the plasma into a bounded domain. In most of the cases, such configurations are obtained by using strong magnetic fields. Several models exist for describing…

Analysis of PDEs · Mathematics 2012-07-11 Mihai Bostan

We perform first-principles relativistic particle-in-cell simulations of aligned pulsar magnetosphere. We allow free escape of particles from the surface of a neutron star and continuously populate the magnetosphere with neutral pair plasma…

High Energy Astrophysical Phenomena · Physics 2015-10-08 Alexander Philippov , Anatoly Spitkovsky

Recent developments in the design of magnetic confinement fusion devices have allowed the construction of exceptionally optimized stellarator configurations. The near-axis expansion in particular has proven to enable the construction of…

Plasma Physics · Physics 2024-04-16 P. A. Figueiredo , R. Jorge , J. Ferreira , P. Rodrigues

Topologically distinct magnetic structures like skyrmions, domain walls, and the uniformly magnetized state have multiple applications in logic devices, sensors, and as bits of information. One of the most promising concepts for applying…

A magnetically dominated plasma driven by motions on boundaries at which magnetic field lines are anchored is forced to dissipate the work being done upon it, no matter how small the electrical resistivity. Numerical experiments have…

Astrophysics · Physics 2007-05-23 Aake Nordlund

In this paper, the design of the the plasma equilibrium and superconducting coils for the Electrons and Positrons in an Optimized Stellarator EPOS experiment is presented. With newly developed stellarator optimization tools, including…

We formulate variation principle for force-free magnetosphere of an inclined pulsar: ${\cal E} +{\bf \Omega}\cdot {\bf M}$ ($\cal E$, ${\bf M}$ are electromagnetic energy and angular momentum, ${\bf \Omega}$ is the angular velocity of a…

Astrophysics · Physics 2009-11-11 Andrei Gruzinov

This paper studies the problem of finding a three-dimensional solenoidal vector field such that both the vector field and its curl are tangential to a given family of toroidal surfaces. We show that this question can be translated into the…

Analysis of PDEs · Mathematics 2023-08-14 Naoki Sato , Michio Yamada

We analyze the chiral magnetic effect in a homogeneous neutral plasma from the point of view of energy conservation, and construct an effective potential for the growth of maximally helical perturbations of the electromagnetic field. We…

High Energy Physics - Phenomenology · Physics 2017-07-19 David B. Kaplan , Sanjay Reddy , Srimoyee Sen

We use three dimensional magnetohydrodynamic simulations to study the structure of the boundary layer between an accretion disc and a non-rotating, unmagnetized star. Under the assumption that cooling is efficient, we obtain a narrow but…

Astrophysics · Physics 2009-11-07 Philip J. Armitage

Magnetic fields are important at every scale in the star formation process: from the dynamics of the ISM in galaxies, to the collapse of turbulent molecular clouds to form stars and in the fragmentation of individual star forming cores. The…

Astrophysics · Physics 2008-04-30 Daniel J. Price , Matthew R. Bate , Clare L. Dobbs

The confinement of heat in the core of a magnetic fusion reactor is optimised using a multidimensional optimisation algorithm. For the first time in such a study, the loss of heat due to turbulence is modelled at every stage using…

Plasma Physics · Physics 2018-10-24 E. G. Highcock , N. R. Mandell , M. Barnes , W. Dorland

Polarization data from high mass star formation regions (W51 e2/e8, Orion BN/KL) are used to derive statistical properties of the plane of sky projected magnetic field. Structure function and auto-correlation function are calculated for…

Solar and Stellar Astrophysics · Physics 2015-05-19 Patrick M. Koch , Ya-Wen Tang , Paul T. P. Ho

We propose to build a Flexible Stellarator Physics Facility to explore promising regions of the vast parameter space of disruption-free stellarator solutions for Fusion Pilot Plants (FPPs).

The dipolar magnetic field structure of the neutron star is modified by the plasma originating in the pulsar magnetopshere. In the simplest case of a stationary axisymmetric force-free magnetosphere, a self-consistent description of the…

High Energy Astrophysical Phenomena · Physics 2015-06-12 S. A. Petrova

Most studies of the pulsar magnetosphere have assumed a pure magnetic dipole in flat spacetime. However, recent work suggests that the effects of general relativity are in fact of vital importance and that realistic pulsar magnetic fields…

High Energy Astrophysical Phenomena · Physics 2016-12-21 Samuel E. Gralla , Alexandru Lupsasca , Alexander Philippov

We report results from calculations investigating stationary magnetic field configurations in accretion discs around magnetised neutron stars. Our strategy is to start with a very simple model and then progressively improve it providing…

Solar and Stellar Astrophysics · Physics 2014-11-20 L. Naso , J. C. Miller

Recent spectro-polarimetric observations of solar-type stars have shown the presence of photospheric magnetic fields with a predominant toroidal component. If the external field is assumed to be current-free it is impossible to explain…

Solar and Stellar Astrophysics · Physics 2016-12-21 Alfio Bonanno

The angular momentum (AM) evolution of stellar interiors, along with the resulting rotation rates of stellar remnants, remains poorly understood. Asteroseismic measurements of red giant stars reveal that their cores rotate much faster than…

Solar and Stellar Astrophysics · Physics 2019-03-08 Jim Fuller , Anthony L. Piro , Adam S. Jermyn

Topology optimization offers great opportunities to design permanent magnetic systems that have specific external field characteristics. Additive manufacturing of polymer bonded magnets with an end-user 3D printer can be used to manufacture…