Periodic Poisson Solver for Particle Tracking

A method is described to solve the Poisson problem for a three dimensional source distribution that is periodic into one direction. Perpendicular to the direction of periodicity a free space (or open) boundary is realized. In beam physics, this approach allows to calculate the space charge field of a continualized charged particle distribution with periodic pattern. The method is based on a particle mesh approach with equidistant grid and fast convolution with a Green's function. The periodic approach uses only one period of the source distribution, but a periodic extension of the Green's function. The approach is numerically efficient and allows the investigation of periodic- and pseudo-periodic structures with period lengths that are small compared to the source dimensions, for instance of laser modulated beams or of the evolution of micro bunch structures. Applications for laser modulated beams are given.Comment: 33 pages, 22 figure

Plasma catecholamines during activation of the sympathetic nervous system in a patient with Shy-Drager syndrome.

Plasma catecholamines and circulation parameters were studied in a patient with a Shy-Drager syndrome. Basal values of free noradrenaline and dopamine were within the normal range, whereas the adrenaline level was decreased. The response of plasma catecholamines to different kinds of physical activity was pathological. The inability to maintain elevated catecholamine levels during prolonged activity corresponded to impaired circulatory regulation and may provide an additional tool for diagnosis and monitoring of the Shy-Drager syndrome

Exciting Collective Oscillations in a Trapped 1D Gas

We report on the realization of a trapped one dimensional Bose gas and its characterization by means of measuring its lowest lying collective excitations. The quantum degenerate Bose gas is prepared in a 2D optical lattice and we find the ratio of the frequencies of the lowest compressional (breathing) mode and the dipole mode to be $(\omega_B/\omega_D)^2\simeq3.1$, in accordance with the Lieb-Liniger and mean-field theory. For a thermal gas we measure $(\omega_B/\omega_D)^2\simeq4$. By heating the quantum degenerate gas we have studied the transition between the two regimes. For the lowest number of particles attainable in the experiment the kinetic energy of the system is similar to the interaction energy and we enter the strongly interacting regime.Comment: 4 pages, 4 figure