ELECTROMAGNETIC ELECTRON-CYCLOTRON WAVES WITH AC FIELD IN THE MAGNETOSPHERE

2014 ◽  
Vol 5 (2) ◽  
pp. 757-766 ◽  
Author(s):  
Rajbir Kaur ◽  
R.S. Pandey ◽  
S. Kumar ◽  
B.S. Tomar

In this paper the effect of externally injected beam of cold electrons on electromagnetic electron-cyclotron (EMEC) waves in the magnetosphere has been discussed. The investigation is conducted using the methodology of characteristic solution and considering kappa distribution function in the presence of AC field.  The objective of present study is to examine the variation in growth rate of EMEC waves when temperature anisotropy, magnitude of AC field and number density of energetic particles varies. It is inferred that EMEC waves grow more significantly when propagating oblique to magnetic field direction rather than parallel to magnetic field direction. Also that as the temperature anisotropy and number density of background plasma increases, growth rate of EMEC waves increases.

2017 ◽  
Vol 6 (4) ◽  
pp. 90-100
Author(s):  
R. Kaur ◽  
R. S. Pandey

In this paper, we investigate the electromagnetic electron cyclotron (EMEC) waves in the magnetosphere of Uranus. By using the method of characteristic solution, the expression for dispersion relation is drawn. Following kinetic approach, the growth rate and real frequency of EMEC waves is studied theoretically, considering the injection of cold plasma beam in the Uranian system. The observations made by a space probe launched by NASA, Voyager 2, showed unusual orientation of planet’s spin axis and presence of more particles in high energy tail in Uranian magnetospheric plasma. Therefore, in this paper Kappa distribution is employed instead of usual Maxwellian distribution. The study is extended to the parallel as well as the oblique propagation of EMEC waves with variation in temperature anisotropy, number density of electrons and angle of propagation with respect to magnetic field direction. It is found that these parameters support the growth rate of EMEC waves. But response of real frequency of these waves is not same as that of growth rate for all the cases. Numerical analysis also revealed that as the ratio of number density of cold to hot plasma increases growth rate of EMEC waves also increases. Thus, denser the beam is injected, more the growth can be observed. These results are appropriate for applications to space plasma environments and magnetospheric regimes for detailed comparative planetary study.


1998 ◽  
Vol 5 (3) ◽  
pp. 937-939 ◽  
Author(s):  
Nobuhiko Sakai ◽  
Hiroshi Ohkubo ◽  
Yasushi Nakamura

A 3 T superconducting magnet has been designed and constructed for magnetic Compton-profile (MCP) measurements with the new capabilities that the magnetic field direction can be altered quickly (within 5 s) and liquid-He refill is not required for more than one week. For the latter capability, two refrigerators have been directly attached to the cryostat to maintain the low temperature of the radiation shields and for the recondensation of liquid He. The system has been satisfactorily operated for over one week.


1997 ◽  
Vol 163 ◽  
pp. 799-800
Author(s):  
Craig H. Smith ◽  
Christopher M. Wright ◽  
David K. Aitken ◽  
Patrick F. Roche

AbstractWe present the results from mid-infrared spectro-polarimetric observations of a number of bi-polar outflow sources. The specto-polarimetric data provides information on the polarization mechanism and the magnetic field direction. The field direction in the disks of the observed sources is most often normal to the ambient field direction and lies in the plane of the disk, indicating a toroidal rather than poloidal field configuration.


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