155 research outputs found
Radiative activity of magnetic white dwarf undergoing Lorentz-force-driven torsional vibrations
We study radiative activity of magnetic white dwarf undergoing torsional
vibrations about axis of its own dipole magnetic moment under the action of
Lorentz restoring force. It is shown that pulsating white dwarf can convert its
vibration energy into the energy of magneto-dipole emission, oscillating with
the frequency equal to the frequency of Alfv\'en torsional vibrations, provided
that internal magnetic field is decayed. The most conspicuous feature of the
vibration energy powered radiation in question is the lengthening of periods of
oscillating emission; the rate of period elongation is determined by the rate
magnetic field decay.Comment: Mod. Phys. Lett. A 26 (2011) 359-36
Orbital and spin scissors modes in superfluid nuclei
Nuclear scissors modes are considered in the frame of Wigner function moments
method generalized to take into account spin degrees of freedom and pair
correlations simultaneously. A new source of nuclear magnetism, connected with
counter-rotation of spins up and down around the symmetry axis (hidden angular
momenta), is discovered. Its inclusion into the theory allows one to improve
substantially the agreement with experimental data in the description of
energies and transition probabilities of scissors modes in rare earth nuclei.Comment: arXiv admin note: text overlap with arXiv:1301.251
A new type of nuclear collective motion - the spin scissors mode
The coupled dynamics of low lying modes and various giant resonances are
studied with the help of the Wigner Function Moments method on the basis of
Time Dependent Hartree-Fock equations in the harmonic oscillator model
including spin-orbit potential plus quadrupole-quadrupole and spin-spin
residual interactions. New low lying spin dependent modes are analyzed. Special
attention is paid to the spin scissors mode.Comment: 21 page
Vibration Powered Radiation of Quaking Magnetar
In juxtaposition with the standard model of rotation powered pulsar, the
model of vibration powered magnetar undergoing quake-induced torsional Alfven
vibrations in its own ultra strong magnetic field experiencing decay is
considered. The presented line of argument suggests that gradual decrease of
frequencies (lengthening of periods) of long-periodic pulsed radiation detected
from a set of X-ray sources can be attributed to magnetic-field-decay induced
energy conversion from seismic vibrations to magneto-dipole radiation of
quaking magnetar.Comment: Text of talk presented at "Mini-Workshop on Pulsars", Nov. 12th,
2010; KIAA-PKU, Beijin
Alfven seismic vibrations of crustal solid-state plasma in quaking paramagnetic neutron star
Magneto-solid-mechanical model of two-component, core-crust, paramagnetic
neutron star responding to quake-induced perturbation by differentially
rotational, torsional, oscillations of crustal electron-nuclear solid-state
plasma about axis of magnetic field frozen in the immobile paramagnetic core is
developed. Particular attention is given to the node-free torsional
crust-against-core vibrations under combined action of Lorentz magnetic and
Hooke's elastic forces; the damping is attributed to Newtonian force of shear
viscose stresses in crustal solid-state plasma. The spectral formulae for the
frequency and lifetime of this toroidal mode are derived in analytic form and
discussed in the context of quasi-periodic oscillations of the X-ray outburst
flux from quaking magnetars. The application of obtained theoretical spectra to
modal analysis of available data on frequencies of oscillating outburst
emission suggests that detected variability is the manifestation of crustal
Alfven's seismic vibrations restored by Lorentz force of magnetic field
stresses.Comment: 10 pages, 10 figure
Hexakis(dimethylformamide)bis(hexaphenylcyclohexasiloxanehexaolato)hexacopper(II) Dimethylformamide Solvate
The sandwich-like title complex, hexakis(dimethylformamide)-1O,2O,3O,4O,5O,6O-bis[2,4,6,8,10,12-hexaphenylsiloxane-2,4,6,8,10,12-hexaolato(6-)-1:22O1,2:32O2,3:42O3,- 4:52O4,5:62O5,1:62O6]hexacopper(II) tetrakis(dimethylformamide) solvate, [Cu6(C3H7NO)6{(C6H5)6O12Si6}2].4C3H7NO, is comprised of two regular crown-shaped macrocyclic hexadentate organosiloxanolate ligands chelating a flat Cu6 hexagon, as in the ethanol-solvated analogue investigated previously. The title complex has a more distorted shape than the trigonal ethanol-solvated analogue, being slightly side-oblated, but still contains a large empty inner channel accessible by small molecules (the diameter of the free cross-section being about 2.5 Ă…). Each CuII ion has square-pyramidal coordination with four basal siloxanolate O atoms and an apical dimethylformamide (DMFA) molecule (coordinated through its carbonyl group). The average bond lengths are: Cu-O(Si) 1.964 (11) Ă… and Cu-O(DMFA) 2.215 (10) Ă…. The structure contains four additional DMFA molecules per complex unit, linked by weak C-HO hydrogen bonds. Unexpectedly, the C=O bond length is longer [1.248 (10) and 1.255 (9) Ă…] in the uncoordinated DMFA molecules than in the coordinated [1.214-1.227 (7) Ă…]
- …