[en] The physical properties of atoms in superstrong magnetic fields, characteristic of neutron stars, and the possibility of detecting magnetically strongly shifted atomic lines in the spectra of magnetized X-ray pulsars are discussed. It is suggested that it is recommendable to look for magnetically strongly shifted Fe 26 Lyman lines in rotating neutron stars of not too high luminosity using spectrometers working in the energy range 10 - 20 keV, with sensitivities to minus 4 power photons per sq cm and second, and resolution E/delta E approx. 10-100

[en] In the modeling of low temperature plasma devices, e.g. glow discharges, the particle-in-cell-Monte-Carlo-collision (PIC-MCC) method has gained increasing importance. The large numerical expenditure, however, has so far limited the number of tractable problems. One reason for this is the fact that the particle simulation has to resolve the smallest scales of a problem. Realistic plasma devices such as the dc glow discharge always possess a number of essentially different time scales: fast electron motion in the cathode fall and slow ion drift in the plasma bulk. Therefore, to obtain convergence, a large number of simulation cycles is necessary. In the past, different methods were developed to cope with the multiple time scale problem: in implicit PIC an increase of the electron time step beyond 1/ω_pe, is possible. This method is not suitable for the modeling of glow discharges, where the time step is limited by the requirement that the particle trajectories between successive collisions must be resolved. Another very simple procedure is the reduction of the ion-electron mass ratio. This also is not suitable for our purposes because it influences the mobility and the drift motion. To overcome the problem of multiple time scales in the modeling of low temperature plasma devices, we have developed a new method, which we call asynchronous cycling. It is designed to manage situations with changes in the macroscopic quantities slower than the ion motion

[en] We provide the relevant formulae for electromagnetic transitions in strong magnetic fields, and apply them to the hydrogen atom. For magnetic field strengths in the range 2.35 x 10¹¹ to 4.7 x 10¹² gauss, which are characteristic of neutron stars, we calculate dipole strengths, oscillator strengths, sum rules, asymptotic formulae, transition probabilities, lifetimes, and intensities

[en] We review recent results of investigations of hydrogen-like systems at magnetic field strengths where the Lorentz forces are comparable to, or larger than, the Coulomb binding forces. This situation is realized for low-lying states at field strengths typical of magnetic white dwarfs and neutron stars, while for Rydberg states already laboratory field strengths are sufficient. We discuss the wavelength spectrum of the hydrogen atom in magnetic fields of arbitrary strength, and describe in which way the spectroscopy of 'stationary lines', which appear in this spectrum, has made possible the detection of the largest magnetic field strength ever found in a white dwarf star to date. For Rydberg states in strong laboratory fields we perform a quantitative comparison between experimental and theoretical spectra, and demonstrate that symptoms of 'quantum stochasticity' are recovered in the spectra of magnetized Rydberg atoms. In particular we point out that the breakdown of quasi-separability in the quantal problem is closely related to the disappearance of regular orbits in the classical problem. We conclude that magnetized Rydberg atoms lend themselves as ideal objects in which to study, theoretically and experimentally, manifestations of quantum stochasticity. (orig.)

[en] The paper reviews the results obtained so far in recalculating the processes of one-photon and two-photon pair annihilation and creation in strong magnetic fields (B approx. 10¹¹ -10¹³ G, as are characteristic of neutron stars), with special emphasis being laid on annihilation. 5 references, 4 figures

[en] Since it has been demonstrated that antiprotons can be captured in sizeable amounts in ion traps, the intriguing question has been raised whether or not these antiprotons can be used for producing antihydrogen atoms. One route proposed is the merging of trapped antiprotons with a cold trapped plasma of positrons. In this case the formation of antihydrogen proceeds most likely through three-body recombination (p^-e⁺e⁺→anti He⁺) into high Rydberg states of anti H, followed by a rapid cascade of transitions to low-lying states. To assess the influence of the trapping magnetic field (on the order of a few tesla) upon the formation process of anti H we review the present knowledge of the behaviour and properties of hydrogen (and antihydrogen) atoms in strong magnetic fields, a subject which has been very topical in recent years because of its relation to the problem of 'quantum' chaos. (orig.)

No abstract available

[en] Using accurate numerical wave functions within the adiabatic approximation, we calculate transition rates for the hydrogen atom in strong magnetic fields (of order 10¹⁰--10¹² gauss, which are assumed for neutron stars), and compare with variational results of Wadehra. An error inherent in his work is pointed out. It is found that using numerical wave functions within the adiabatic approximation leads to values for the transition rates which are larger than the ones of the variational calculation by about 15%

No abstract available

[en] The paper analyses the elementary electron-ion bremsstrahlung process for magnetic field strengths of the order 10⁷-10⁹ T, which are present in plasmas in the vicinity of neutron stars. The general expression of the (non-relativistic) cross section is given, assuming electrons in the ground-state Landau level, and various approximations to it are discussed. Detailed results are presented for the dependence of the cross section on the magnetic field strength, the primary electron energy, and the energy, polarisation, and solid angle of the emitted bremsstrahlung photons. (author)