Dynamics and Energy Dissipation of a Rigid Dipole Driven by the RF-field in a Viscous Fluid: Deterministic Approach

The deterministic rotation of a ferromagnetic nanoparticle in a fluid is considered. The heating arising from viscous friction of a nanoparticle driven by circularly and linearly polarized alternating magnetic fields is investigated. Since the power loss of such fields depends on the character of the induced motion of a nanoparticle, all types of particle trajectories are described in detail. The dependencies of the power loss on the alternating field parameters are determined. The optimal conditions for obtaining the maximum heating efficiency are discussed. The effect of heating enhancement by a static field is analyzed. The results obtained are actual for the description of heating in the magnetic fluid hyperthermia cancer treatment, when the size of the particles used is a few tens of nanometers

Large-scale Ferrofluid Simulations on Graphics Processing Units

We present an approach to molecular-dynamics simulations of ferrofluids on graphics processing units (GPUs). Our numerical scheme is based on a GPU-oriented modification of the Barnes-Hut (BH) algorithm designed to increase the parallelism of computations. For an ensemble consisting of one million of ferromagnetic particles, the performance of the proposed algorithm on a Tesla M2050 GPU demonstrated a computational-time speed-up of four order of magnitude compared to the performance of the sequential All-Pairs (AP) algorithm on a single-core CPU, and two order of magnitude compared to the performance of the optimized AP algorithm on the GPU. The accuracy of the scheme is corroborated by comparing the results of numerical simulations with theoretical predictions

Directed transport in periodically rocked random sawtooth potentials

We study directed transport of overdamped particles in a periodically rocked random sawtooth potential. Two transport regimes can be identified which are characterized by a nonzero value of the average velocity of particles and a zero value, respectively. The properties of directed transport in these regimes are investigated both analytically and numerically in terms of a random sawtooth potential and a periodically varying driving force. Precise conditions for the occurrence of transition between these two transport regimes are derived and analyzed in detail.Comment: 18 pages, 7 figure