Frequency shifts of a two-mode He–Ne/CH4laser stabilized by frequency resonances, under the action of a magnetic field in the active medium

1990 ◽  
Vol 20 (5) ◽  
pp. 511-514
Author(s):  
M A Gubin ◽  
A V Nikul'chin ◽  
E D Protsenko ◽  
A N Rurukin
Keyword(s):  
Magnetic Field ◽  
Active Medium ◽  
Frequency Shifts

scholarly journals Исследования альфвеновских мод на токамаке Глобус-М2 с использованием многочастотного допплеровского рефлектометра V-диапазона

2021 ◽  
Vol 47 (4) ◽  
pp. 41
Author(s):  
В.В. Буланин ◽  
И.М. Балаченков ◽  
В.И. Варфоломеев ◽  
В.К. Гусев ◽  
Г.С. Курскиев ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Doppler Frequency ◽  
Spherical Tokamak ◽  
Frequency Shifts ◽  
Toroidal Plasma ◽  
V Band ◽  
New Information ◽  
Spectral Components ◽  
Central Regions ◽  
Doppler Frequency Shifts

New information on the development of Alfvén modes in the Globus-M2 spherical tokamak is presented. The data were obtained using a V-band Doppler reflectometer with probing radiation frequencies from 50 to 75 GHz. A microwave harmonic synthesizer was used as a multifrequency probing source. As a result of using a new reflectometer, the localization of the toroidal Alfvén eigenmode has been determined at a magnetic field of 0.5 T. The spectral components of the Alfvén mode with Doppler frequency shifts due to toroidal plasma rotation have been recorded. The so-called Alfvén cascades have been investigated in the central regions of the discharge.

scholarly journals Period spacings of gravity modes in rapidly rotating magnetic stars

2020 ◽  
Vol 636 ◽  
pp. A100 ◽  
Author(s):  
V. Prat ◽  
S. Mathis ◽  
C. Neiner ◽  
J. Van Beeck ◽  
D. M. Bowman ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Rotation Axis ◽  
Equatorial Region ◽  
Rotating Stars ◽  
Frequency Shifts ◽  
New Formalism ◽  
Magnetic Stars ◽  
Internal Oblique ◽  
Rapidly Rotating Stars ◽  
The Magnetic Field

Context. Stellar internal magnetic fields have recently been shown to leave a detectable signature on period spacing patterns of gravity modes. Aims. We aim to investigate the effect of the obliquity of a mixed (poloidal and toroidal) dipolar internal fossil magnetic field with respect to the rotation axis on the frequency of gravity modes in rapidly rotating stars. Methods. We used the traditional approximation of rotation to compute non-magnetic modes, and a perturbative treatment of the magnetic field to compute the corresponding frequency shifts. We applied the new formalism to HD 43317, a magnetic, rapidly rotating, slowly pulsating B-type star, whose field has an obliquity angle of about 80°. Results. We find that frequency shifts induced by the magnetic field on high-radial-order gravity modes are larger with increasing obliquity angle, when the magnetic axis is closer to the equatorial region, where these modes are trapped. The maximum value is reached for an obliquity angle of 90°. This trend is observed for all mode geometries. Conclusions. Our results predict that the signature of an internal oblique dipolar magnetic field is detectable using asteroseismology of gravity modes.

Theory of Raman sidescatter from a magnetized plasma

1984 ◽  
Vol 32 (2) ◽  
pp. 331-346 ◽  
Author(s):  
H. C. Barr ◽  
T. J. M. Boyd ◽  
R. Rankin
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Wave ◽  
Growth Rates ◽  
Scattered Light ◽  
Critical Density ◽  
Magnetized Plasma ◽  
Frequency Shifts ◽  
Wave Growth ◽  
Circularly Polarized ◽  
The Magnetic Field

The effects of a d.c. magnetic field on stimulated Raman sidescatter from laser-produced plasmas is studied. For exact sidescatter along the magnetic field, the Raman instability separates into two distinct decays in which the scattered light is either a right (RHCP) or left (LHCP) circularly polarized electromagnetic wave. Growth rates of the instabilities can be enhanced in the former case but are diminished in the latter. The magnetic field induced effects are greatest near the quarter critical density where frequency shifts can be especially significant, being equal to ± ¼Ωc for decay into RHCP and LHCP waves, respectively.

scholarly journals Effect of a Steady Flow and an Atmospheric Magnetic Field on the Solar p- and f-Modes

2001 ◽  
Vol 203 ◽  
pp. 208-210 ◽  
Author(s):  
R. Erdélyi ◽  
Y. Taroyan
Keyword(s):  
Magnetic Field ◽  
Simple Model ◽  
Uniform Magnetic Field ◽  
The Sun ◽  
Equilibrium Flow ◽  
Frequency Shifts ◽  
Homogeneous Flow ◽  
Long Wavelength ◽  
Long Wavelength Approximation ◽  
Wavelength Approximation

The combined effect of a subsurface steady homogeneous flow and a chromospheric uniform magnetic field on the solar p- and f-modes is evaluated theoretically for a simple model of the Sun. The derived dispersion relation is solved analytically in limit of the long wavelength approximation and is evaluated numerically for arbitrary wavelengths. The influence of an equilibrium flow is more dominant in limit of small wavenumbers. For arbitrary wavelengths the effect of a magnetic field might be stronger than frequency shifts caused by a steady homogeneous flow.

Search for Zeeman-splitting of OH 6.035 GHz line in the young planetary nebula K 3-35

2020 ◽  
Vol 495 (4) ◽  
pp. 4326-4333
Author(s):  
L G Hou ◽  
X Y Gao
Keyword(s):  
Magnetic Field ◽  
Circular Polarization ◽  
Planetary Nebula ◽  
Zeeman Splitting ◽  
Line Of Sight ◽  
State Transitions ◽  
Frequency Shifts ◽  
Left Hand ◽  
Emission Component ◽  
Source Of Information

ABSTRACT Magnetic field could play a role in the formation and early evolution of non-spherical planetary nebulae (PNe). The predominant source of information of the magnetic fields in PNe is the polarization observations of maser emission. To date, distinct and/or possible Zeeman pairs have only been reported towards four PNe by measuring the OH ground-state transitions at 1.6–1.7 GHz. With the C-band (4–8 GHz) receiving system of the Shanghai TianMa 65-m radio telescope, we aim to search for possible Zeeman pairs of the PNe towards which the OH excited-state 6.035 GHz maser lines have been detected. For the young PN K 3-35, a new emission component near VLSR = 20.5 km s−1, which is currently the strongest (Ipeak ∼ 0.3 Jy) among the four components towards K 3-35 is detected. A clear S-shaped feature corresponding to this new emission component is observed in the Stokes V spectrum. Frequency shifts are seen between the fitted left-hand circular polarization and right-hand circular polarization emission peaks for the two emission components near VLSR = 19.7 and 20.5 km s−1. If the S-shaped profile and the frequency shifts are the results of Zeeman-splitting, the line-of-sight magnetic field strengths of +2.9 ± 0.6 and +4.5 ± 0.4 mG can be inferred for these two emission components, respectively.

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