scholarly journals Particle Acceleration in Spherical Wave Fields

1992 ◽  
Vol 128 ◽  
pp. 109-111
Author(s):  
K. O. Thielheim
Keyword(s):  
Particle Acceleration ◽  
Dipole Moment ◽  
Angular Velocity ◽  
Neutron Stars ◽  
Magnetic Dipole ◽  
Magnetic Dipole Moment ◽  
Spherical Wave ◽  
Particle Accelerator ◽  
Dynamic Features ◽  
Wave Fields

A magnet rotating in vacuo with its vector of angular velocity ω perpendicular to its vector of magnetic dipole moment μ is able to act as a particle accelerator. The dynamic features involved may be relevant for the understanding of rotating magnetized neutron stars as cosmic accelerators (Thielheim 1989) and may be useful for the designing of new mechanisms for accelerating devices.

scholarly journals Cosmic Ray Particle Acceleration in Pulsar Magnetospheres

1987 ◽  
Vol 125 ◽  
pp. 555-555 ◽  
Author(s):  
K.O. Thielheim
Keyword(s):  
Particle Acceleration ◽  
Dipole Moment ◽  
Magnetic Dipole ◽  
Magnetic Dipole Moment ◽  
Cosmic Ray ◽  
Field Configuration ◽  
Vacuum Field ◽  
Particle Accelerators ◽  
Typical Parameter ◽  
Parameter Values

A plausible approach to the theory of pulsars as cosmic ray particle accelerators is to integrate numerically the Lorentz-Dirac-equation, using the vacuum field of a rotating orthogonal magnetic dipole as a model field configuration. Typical parameter values are: angular velocity ω = 20 π/sec and magnetic dipole moment μ = 1030G cm3 (K.O. Thielheim, Proc. ESO-CERN Conf. 1986).

scholarly journals 2D Frozen spin method of searching for the deuteron EDM in a storage ring

2019 ◽  
Author(s):  
Alexander Aksentev
Keyword(s):  
Dipole Moment ◽  
Angular Velocity ◽  
Magnetic Dipole ◽  
Magnetic Dipole Moment ◽  
Spin Dynamics ◽  
Vertical Plane ◽  
Lorentz Factor ◽  
Spin Precession ◽  
Precession Frequency ◽  
Spin Decoherence

The purpose of the present work is the development of a method for searching the electric dipole moment (EDM) of the deuteron inside the storage ring environment using the frozen spin method. The 2D frozen spin method is a variation on the original frozen spin method proposed at Brookhaven National Laboratory, in which the beam polarisation vector freely precesses in the vertical plane. One distinguishing feature of the 2D frozen spin method, is that it uses the radial magnetic fields induced by the accelerator optical lattice's imperfections to drive the vertical plane precession. The net electric + magnetic dipole moment spin precession frequency is measured. The EDM estimator is constructed as the sum of the net frequency estimates in two cases: when the beam circulates clockwise (CW), and when it does counter-clockwise (CCW). For the deuteron, since the experiment is performed in a combined ring, the beam circulation direction change requires flipping the polarity of the guiding magnetic field. When this is done, the imperfection fields change their sign as well, and so does the magnetic dipole moment (MDM) component of the spin precession angular velocity vector. Therefore, theoretically, the MDM term cancels in the EDM estimator. The trick is to calibrate the MDM precession frequency with sufficient precision. For that purpose, the concept of the effective Lorentz factor was introduced. We try to prove that particles having equal values of the effective Lorentz factor have equal spin tunes (and invariant spin axis orientations as well), and therefore, by controlling a single parameter -- the effective Lorentz factor -- it is possible to calibrate the MDM component of the precession frequency. A special calibration procedure is numerically modelled, with the conclusion that it allows sufficiently precise MDM spin precession frequency reproduction. Three major systematic effects of spin dynamics have been analysed: 1) perturbations to the particle spin dynamics caused by betatron oscillations, 2) spin decoherence in the zero spin resonance (frozen spin) region, 3) properties of the machine imperfection MDM spin precession angular velocity. We conclude that the first systematic effect is negligible; analyse the sextupole field approach to suppressing spin decoherence, and find it effective; find that the imperfections systematic error is linear, but asymmetric with respect to the beam circulation direction, which is more motivation for using the effective Lorentz factor as the tool for calibrating the MDM spin precession frequency. Overall, we find the proposed method effective.

scholarly journals Pseudospin versus magnetic dipole moment ordering in the isosceles triangular lattice material K3Er(VO4)2

2020 ◽  
Vol 102 (10) ◽  
Author(s):  
Danielle R. Yahne ◽  
Liurukara D. Sanjeewa ◽  
Athena S. Sefat ◽  
Bradley S. Stadelman ◽  
Joseph W. Kolis ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Magnetic Dipole ◽  
Triangular Lattice ◽  
Magnetic Dipole Moment ◽  
Lattice Material

scholarly journals Stellar activity and magnetic shielding

2009 ◽  
Vol 5 (S264) ◽  
pp. 385-394 ◽  
Author(s):  
J.-M. Grießmeier ◽  
M. Khodachenko ◽  
H. Lammer ◽  
J. L. Grenfell ◽  
A. Stadelmann ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Magnetic Dipole ◽  
Magnetic Dipole Moment ◽  
Direct Interaction ◽  
Planetary Atmosphere ◽  
Stellar Activity ◽  
Planetary Environment ◽  
Atmospheric Loss ◽  
Planetary Magnetic Field ◽  
Planetary Habitability

AbstractStellar activity has a particularly strong influence on planets at small orbital distances, such as close-in exoplanets. For such planets, we present two extreme cases of stellar variability, namely stellar coronal mass ejections and stellar wind, which both result in the planetary environment being variable on a timescale of billions of years. For both cases, direct interaction of the streaming plasma with the planetary atmosphere would entail servere consequences. In certain cases, however, the planetary atmosphere can be effectively shielded by a strong planetary magnetic field. The efficiency of this shielding is determined by the planetary magnetic dipole moment, which is difficult to constrain by either models or observations. We present different factors which influence the strength of the planetary magnetic dipole moment. Implications are discussed, including nonthermal atmospheric loss, atmospheric biomarkers, and planetary habitability.

Exotic-atom measurement of the magnetic dipole moment of theΣ−hyperon

1988 ◽  
Vol 37 (5) ◽  
pp. 1142-1152 ◽  
Author(s):  
D. W. Hertzog ◽  
M. Eckhause ◽  
P. P. Guss ◽  
D. Joyce ◽  
J. R. Kane ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Magnetic Dipole ◽  
Magnetic Dipole Moment ◽  
Exotic Atom
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