Related papers: First order Fermi acceleration driven by magnetic …
We exploit analogies between first-order algorithms for constrained optimization and non-smooth dynamical systems to design a new class of accelerated first-order algorithms for constrained optimization. Unlike Frank-Wolfe or projected…
Magnetic reconnection in the relativistic and trans-relativistic regimes is able to accelerate particles to hard power law energy spectra $f \propto \gamma^{-p}$ (approaching $p=1$). The underlying acceleration mechanism that determines the…
The interaction of a plane gravitational wave with test masses can be described in the proper detector frame, using Fermi coordinates, in terms of a gravitoelectric and a gravitomagnetic field. We use this approach to calculate the…
By means of fully kinetic particle-in-cell simulations, we study whether the proton-to-electron mass ratio $m_i/m_e$ influences the energy spectrum and underlying acceleration mechanism during magnetic reconnection. While kinetic…
In conventional metals, electronic transport in a magnetic field is characterized by the motion of electrons along orbits on the Fermi surface, which usually causes an increase in the resistivity through averaging over velocities. Here we…
Relativistic particle acceleration in collisionless shocks of supernova remnants is accompanied by magnetic field amplification from cosmic ray (CR) driven plasma instabilities. Bell's fast CR-current instability is predicted to produce…
Here is reported in situ observation of energetic electrons (~100-500 keV) associated with magnetic reconnection in the solar wind by the ACE and Wind spacecraft. The properties of this magnetic cloud driving reconnection and the associated…
We investigate quantum revivals in the dynamics of an atom in an atomic Fermi accelerator. It is demonstrated that the external driving field influences the revival time significantly. Analytical expressions are presented which are based on…
The one-particle spectral function and its orbital composition are investigated in a three-orbital model for the undoped parent compounds of the iron-based superconductors. In the realistic parameter regime, where results best fit…
Accelerated first order methods, also called fast gradient methods, are popular optimization methods in the field of convex optimization. However, they are prone to suffer from oscillatory behaviour that slows their convergence when medium…
This work presents an analysis of the ion outflow from magnetic reconnection throughout fully kinetic simulations with typical laboratory plasmas values. A symmetric initial configuration for the density and magnetic field is considered…
We consider a large scale environment of turbulent reconnection that is fragmented into a number of randomly distributed Unstable Current Sheets (UCS), and we statistically analyze the acceleration of particles within this environment. We…
Magnetic reconnection is a fundamental plasma process that is thought to play a key role in the production of nonthermal particles associated with explosive phenomena in space physics and astrophysics. Experiments at high-energy-density…
Diffusive shock acceleration at collisionless shocks is thought to be the source of many of the energetic particles observed in space. Large-scale spatial variations of the magnetic field has been shown to be important in understanding…
We investigate the condition for capture into first-order mean motion resonances using numerical simulations with a wide range of various parameters. In particular, we focus on deriving the critical migration timescale for capture into the…
We derive an analytic expression for the power transferred from interstellar turbulence to the Galactic cosmic rays in propagation models which include re-acceleration. This is used to estimate the power required in such models and the…
We consider a first-order aggregation model in both discrete and continuum formulations and show rigorously how it can be obtained as zero inertia limits of second-order models. In the continuum case the procedure consists in a macroscopic…
We study gradient-based optimization methods obtained by direct Runge-Kutta discretization of the ordinary differential equation (ODE) describing the movement of a heavy-ball under constant friction coefficient. When the function is high…
The ground states and collective excitations of trapped Fermion gases consisting of atoms with magnetic dipole moment are studied using a time-dependent density-matrix approach. The advantages of the density-matrix approach are that…
Mathematics demonstrates that an ideally evolving magnetic field has an exponentially increasing sensitivity to non-ideal effects for all but truly exceptional evolutions. On a time scale that depends only logarithmically on the magnitude…