We followed fragmentation of magnetized lamentary clouds and formation of disks with two-dimensional numerical simulations. A lamentary cloud with longitudinal magnetic elds fragments to form geometrically thin disks perpendicular to the magnetic eld. Each disk collapses self-similarly toward the lament axis, keeping quasi-static equilibrium in the direction parallel to the axis. With some simp...

Chaotic magnetic eld lines play an important role in plasma con nement by tokamaks. They can either be generated in the plasma as a result of natural instabilities or arti cially produced by external conductors, like resonant helical windings and ergodic magnetic limiters. This is a review of works carried out at the Universidade de S~ao Paulo and Universidade Federal do Paran a on theoretical ...

The muon transverse ionization cooling is modeled as a Brownian motion of the muon beam as it traverses a Li or Be rod. A Langevin like equation is written for the free particle case (no external transverse magnetic eld) and for the most realistic harmonically bound beam in the presence of a focusing magnetic eld.

Alfvén waves dissipation is an extensively studied mechanism for the coronal heating problem. These waves can be generated by magnetic reconnection and propagated along the reconnected field lines. Here, we study the generation of Alfvén waves at the presence of both steady flow and sheared magnetic field in the longitudinally density stratified of solar spicules. The initial flow is assumed to...

The Economic Load Dispatch (ELD) problems in power generation systems are to reduce the fuel cost by reducing the total cost for the generation of electric power. This paper presents an efficient Modified Firefly Algorithm (MFA), for solving ELD Problem. The main objective of the problems is to minimize the total fuel cost of the generating units having quadratic cost functions subjected to lim...

Aims. We present a parameter study of the magnetohydrodynamical dynamo driven by cosmic rays in the interstellar medium (ISM) focusing on the efficiency of magnetic field amplification and the issue of energy equipartition between magnetic, kinetic and cosmic

We make the hypothesis that molecular cloud fragments are triaxial bodies with a large scale magnetic field oriented along the short axis. While consistent with theoretical expectations, this idea is supported by magnetic field strength data, which show strong evidence for flattening along the direction of the mean magnetic field. It is also consistent with early submillimeter polarization data...

We consider the classical motion of a particle in a plane domain, under the innuence of a perpendicular magnetic eld and a smooth potential, with elastic reeections on the walls of the domain. We discuss a variational method for nding periodic orbits, determining their stability and proving the existence of KAM tori. This method is applied to a circular scatterer in crossed electromagnetic elds...

We investigate the question of whether ambipolar diffusion (ion-neutral drift) determines the smallest length and mass scale on which structure forms in a turbulent molecular cloud. We simulate magnetized turbulence in a mostly neutral, uniformly driven, turbulent medium, using a three-dimensional, two-fluid, magnetohydrodynamics (MHD) code modified from Zeus-MP. We find that substantial struct...

Paramagnetic alignment of thermally rotating oblate dust grains is studied analytically for finite ratios of grain to gas temperatures. For such ratios, the alignment of angular momentum J in respect to the grain axis of maximal inertia is only partial. We treat the alignment of J using perturbative methods and disentangle the problem of J alignment in grain body axes from that of J alignment i...