FREQUENCY VARIATION IN IONOSPHERIC CYCLOTRON HARMONIC SERIES OBTAINED BY THE ALOUETTE I SATELLITE

1966 ◽  
Vol 44 (5) ◽  
pp. 987-994 ◽  
Author(s):  
R. E. Barrington ◽  
Luise Herzberg

Ionograms produced by the Alouette I topside sounder frequently show well-developed series of cyclotron harmonics. Their frequencies have been determined from A (amplitude) scans with an accuracy of ~0.02 Mc/s for the sweep range of 1 to 6 Mc/s. In all cases examined, the frequencies of all of the members of the harmonic series are, within the experimental accuracy, integral multiples of the cyclotron frequency derived from the best present estimates of the earth's magnetic field strength at the satellite height. This result is discussed in the light of recent laboratory results and theoretical studies.

1973 ◽  
Vol 9 (1) ◽  
pp. 89-100 ◽  
Author(s):  
S. Puri ◽  
F. Leuterer ◽  
M. Tutter

Dispersion curves are plotted for the extraordinary branch of the electron- and ion-cyclotron harmonic waves propagating perpendicularly to the static magnetic field in a non-relativistic, hot Maxwellian plasma, without invoking the electrostatic approximation. It is found that, except in the vicinity of the cyclotron harmonics and the hybrid resonances, either the cold-plasma or the electrostatic approximation are accurate representations of the exact solution. The hybrid resonances of the cold-plasma model become monotonically shrinking regions of low group velocity as the temperature is increased, till all discernible evidence of these resonances disappears as the parameters corresponding to the thermonuclear plasmas are approached.


1979 ◽  
Vol 53 ◽  
pp. 334-340 ◽  
Author(s):  
H.S. Stockman ◽  
James Liebert ◽  
Howard E. Bond

Most theoretical models of the AM Her variables (AM Her, AN UMa, W Pup and 2A0311-22) rely on strong cyclotron emission at the fundamental cyclotron frequency and higher harmonics to produce the observed, strongly-polarized optical continuum (e.g. Lamb and Masters 1979). The cyclotron lines, which presumably originate in the hot, isothermal accretion shock at the surface of the white dwarf (kT ≳ 10 keV, h/R* ≲ 0.1), should be blurred into a continuous spectrum by both optical depth effects and electron Doppler broadening. Thus the lack of even weak cyclotron features in the optical spectra of these objects is still compatible with a cyclotron origin.


Author(s):  
В.В. Амеличев ◽  
Д.А. Жуков ◽  
С.И. Касаткин ◽  
Д.В. Костюк ◽  
О.П. Поляков ◽  
...  

The results of experimental and theoretical studies of the influence of the current value on the characteristics of anisotropic magnetoresistive magnetic field sensors based on FeNiCo alloy with a "barber-polе" structure are presented. A significant difference was found between the volt-oersted characteristics of the forward and reverse strokes with an increase in the intrinsic current caused by the input supply voltage at sufficiently high external magnetic fields. A theoretical calculation of the volt-oersted characteristic was carried out within the framework of the model of one-dimensional heterogeneity of the magnetization distribution, which coincides with the experimental curves of the forward path.


Author(s):  
Saren Gaowa ◽  
Yan-Bo Geng ◽  
Zhao-Hua Ding ◽  
Jing-Lin Xiao

In this research, the effects of magnetism and parabolic potential on strongly coupled polaron characteristics within asymmetric Gaussian quantum wells (AGQWs) were investigated. To do so, the following six parameters were studied, temperature, AGQW barrier height, Gaussian confinement potential (GCP) width, confinement strengths along the directions of [Formula: see text] and [Formula: see text], as well as magnetic field cyclotron frequency. The relationships among frequency oscillation, AGQW parameters and polaron ground state energy in RbCl crystal were studied based on linear combination operator and Lee–Low–Pines unitary transformation. It was concluded that ground state energy absolute value was decreased by increasing GCP width and temperature, and increased with the increase of confinement strength along [Formula: see text] and [Formula: see text] directions, cyclotron frequency of magnetic field and barrier height of AGQW. It was also found that vibrational frequency was increased by enhancing confinement strengths along the directions of [Formula: see text] and [Formula: see text], magnetic field cyclotron frequencies, barrier height AGQW and temperature and decreased with the increase of GCP width.


1967 ◽  
Vol 45 (12) ◽  
pp. 4019-4038 ◽  
Author(s):  
Edmund K. Miller

A numerical investigation of the admittance of an infinite, circular cylindrical antenna excited at a circumferential gap of nonzero thickness, and immersed in a lossy incompressible magnetoplasma with the antenna parallel to the static magnetic field is described. A concentric free-space layer (the vacuum sheath) which separates the antenna from the external uniform plasma is included in the analysis to approximate the positive ion sheath which may form about a body at floating potential in a warm plasma. The numerical results for the antenna admittance show that: (1) in the absence of a sheath, a sharp admittance maximum is found at the electron cyclotron frequency, with the maximum more pronounced when the plasma frequency exceeds the cyclotron frequency than for the converse case; (2) the vacuum sheath shifts upward in frequency and reduces in amplitude the admittance maximum which occurs for the sheathless case at the cyclotron frequency; (3) a kink or minimum in the admittance is found at the plasma frequency.


2020 ◽  
Vol 35 (32) ◽  
pp. 2050265
Author(s):  
S. Mignemi

We discuss the corrections to the orbital period of a particle in a constant magnetic field, driven by the model of noncommutative geometry recently associated to a quantum clock. The effects are extremely small, but in principle detectable.


1971 ◽  
Vol 5 (3) ◽  
pp. 467-474 ◽  
Author(s):  
B. Buti ◽  
G. S. Lakhina

Waves, propagating transverse to the direction of the streaming of a plasma in the presence of a uniform external magnetic field, are unstable if the streaming exceeds a certain minimum value. The magnetic field reduces the growth rate of this instability, and also increases the value of the minimum streaming velocity, above which the system is unstable. The thermal motions in the plasma, however, tend to stabilize the system if the magnetic field is weak (i.e. , Ω being the electron cyclotron frequency, k the characteristic wave-number, and Vt the thermal velocity); but, in case of strong magnetic field (i.e. ), they increase the growth rate, provided (ωp being the electron plasma frequency).


2002 ◽  
Vol 16 (20n22) ◽  
pp. 3238-3243
Author(s):  
A. ARDAVAN ◽  
E. RZEPNIEWSKI ◽  
R. S. EDWARDS ◽  
J. SINGLETON ◽  
Y. MAENO

We report a study of the angle-dependent millimetre-wave magnetoconductivity of the p-wave triplet-paired perovskite superconductor Sr 2 RuO 4. We find two harmonic series. We assign the first to interlayer cyclotron resonance of the β-Fermi surface and its harmonics, yielding a cyclotron effective mass of [Formula: see text]. We assign the second series, which contains only odd harmonics, to cyclotron resonance of the γ-Fermi surface, yielding a cyclotron effective mass of [Formula: see text]. In addition, we find a very strong absorption mode in the presence of a magnetic field component parallel to the quasi-two-dimensional (Q2D) planes of the sample. Its dependence on the orientation of the magnetic field cannot be described in the context of conventional Q2D cyclotron resonance, and the origin of this mode is not yet clear.


1991 ◽  
Vol 45 (3) ◽  
pp. 389-406 ◽  
Author(s):  
K. P. Wessen ◽  
N. F. Cramer

The dispersion relation for low-frequency surface waves at a current sheet between two magnetized plasmas is derived using the cold-plasma dielectric tensor with finite ion-cyclotron frequency. The magnetic field direction is allowed to change discontinuously across the sheet, but the plasma density remains constant. The cyclotron frequency causes a splitting of the dispersion relation into a number of mode branches with frequencies both less than and greater than the ion-cyclotron frequency. The existence of these modes depends in particular upon the degree of magnetic field discontinuity and the direction of wave propagation in the sheet relative to the magnetic field directions. Sometimes two modes can exist for the same direction of propagation. The existence of modes undamped by Alfvén resonance absorption is predicted. Analytical solutions are obtained in the low-frequency and magnetic-field-reversal limits. The solutions are obtained numerically in the general case.


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