Interplanetary transients causing unusual anisotropic wave trains in CR intensity

1Mishra, RK, 2Mishra, RA
1Computer and IT Section, Tropical Forest Research Institute, P. O. RFRC, Mandla Road, Jabalpur (M. P.) 482 021, India
2Department of Physics, Govt. Model Science College (Autonomous), Jabalpur (M. P.) 482 001, India
Kosm. nauka tehnol. 2006, 12 ;(5-6):079-086
Publication Language: English
The study deals with short-term variations of cosmic ray intensity during the interval from 1991 to 1994. The occurrence of a large number of high and low amplitude anisotropic wave train events (HAEs/LAEs) is examined. The correlation between these unusual anisotropic events and SWP/IMF parameters is studied to locate the possible cause responsible for occurrence of these types of events. Our results indicate that the time of maximum of diurnal variation shows a remarkable systematic shift towards earlier hours for LAE; whereas it remains in the 18-Hr direction for HAE. It is also noteworthy that the occurrence of low as well as high amplitude anisotropic wave train events is independent of nature of IMF polarity.
Keywords: correlation, plasma parameters, unusual anisotropic events
1. Agrawal S. P. Ph. D. Thesis. (Gujrat University, Ahmedabad, 1973).
2. Agrawal S. P. Study of tri-diurnal variation of galactic cosmic radiation. J. Geophys. Res., 86, 10115 (1981).
3. Agrawal S. P., Singh R. L. Critical study of the diurnal and semi-diurnal variation of cosmic ray intensity on day-to-day basis. 14thInt. Cosmic Ray Conf., 3, 1253 (1975).
4. Ahluwalia H. S., Riker J. F. Secular changes in the upper cut-off rigidity of the solar diurnal anisotropy of cosmic rays. Planet. Space Sci., 35, 39 (1987).
5. Ananth A. G., Agrawal S. P., Rao U. R. Study of CR diurnal variation on a day-to-day basis. Pramana, 3, 74 (1974).
6. Axford W. I. The modulation of galactic cosmic rays in the interplanetary medium. Planet. Space Sci., 13, 115 (1965).
7. Axford W. I. Anisotropic diffusion of solar cosmic rays. Planet. Space Sci., 13, 1301 (1965).
8. Dorman L. T., Kaminer N. S., Kuzmicheva A. E., Mymrina N. V. Features of diurnal variations of cosmic rays in high-speed streams of the solar wind. Geomag. Aeronomy, 24, 252 (1984).
9. Duggal S. P., Pomerantz M. A. Progressive rotation of cosmic-ray diurnal variation vector. Phys. Rev. Letters, 8 (5), 215ó216 (1962).
10. Fluckiger E. O. Solar and terrestrial modulation. 22nd Int. Cosmic Ray Conf., Dublin, 5, 273 (1991).
11. Hashim A., Bercovitch M. A cosmic ray density gradient perpendicular to the ecliptic plane. Planet. Space Sci., 20, 791 (1972).
12. Iucci N., Parissi M., Storini M., Villoressi G. Cosmic-ray anisotropy during high-speed streams coming from coronal holes. 17thInt. Cosmic Ray Conf., Paris, 10, 238 (1981).
13. Iucci N., Parisi M., Storini M., Villoressi G. The behavior of the cosmic-ray equatorial anisotropy inside fast solar-wind streams ejected by coronal holes. Il Nuovo Cimento, 6C, 145 (1983).
14. Jadhav D. K., Shrivastava M., Tiwari A. K., Shrivastava P. K. Study of semi-diurnal variation of cosmic rays during days of low and high diurnal amplitude wave trains. 18th Int. Cosmic Ray Conf., Bangalore, 3, 337 (1983).
15. Kananen H., Komori H., Tanskanen P., Oksman J. Relation between cosmic-ray anisotropy and sector structure. 17thInt. Cosmic Ray Conf., Paris, 10, 190 (1981).
16. Kumar S. Time variation of cosmic rays: Ph. D. Thesis. (Aligarh Muslim University, Aligarh, 1978).
17. Kumar S., Agarwal R., Mishra R., Dubey S. K. Daily variation in cosmic ray intensity on different geomagnetic conditions. Int. J. Mod. Phys. D, 11, 1243 (2002).
18. Kumar S., Chauhan M. L. Unusually low amplitude anisotropic wave train events in cosmic ray intensity. Ind. J. Radio and Space Phys., 25, 106 (1996).
19. Kumar S., Chauhan M. L. High amplitude anisotropic wave train events in cosmic ray intensity. Ind. J. Radio and Space Phys., 25, 232 (1996).
20. Kumar S., Chauhan M. L., Dubey S. K. Effect of interplanetary turbulences causing high/low amplitude anisotropic wave trains in CR intensity. Solar Phys., 176, 403 (1997).
21. Mathews T.,Venkatesan D., Wilson B. G. Pronounced diurnal variation in cosmic-ray intensity. J. Geophys. Res., 74, 1218 (1969).
22. Mavromichalaki H. The relation of the diurnal variation to the solar rotation and to the interplanetary sector boundaries. 17th Int. Cosmic Ray Conf., Paris, 10, 183 (1981).
23. McCraken K. G., Rao U. R. A survey of the diurnal anisotropy. 9thInt. Cosmic Ray Conf., London, 1, 213 (1965).
24. Munakata Y., Darwish A., Fujii Z., et al. High-speed solar-wind streams from coronal holes and modulation of cosmic ray diurnal anisotropy. 28th Int. Cosmic Ray Conf., Tsukuba, 3925 (2003).
25. Munakata K., Mori S., Ryu J. Y., et al. In: 20thInt. Cosmic Ray Conf., Moscow, 4, 39 (1987).
26. Parker E. N. Theory of streaming of cosmic rays and the diurnal variation. Planet. Space Sci., 12, 735 (1964).
27. Parker E. N. The magnetic field of the Galaxy. 22nd Int. Cosmic Ray Conf., Ireland, 5, 35 (1991).
28. Rao U. R. Solar modulation of galactic cosmic radiation. Space Sci. Rev., 12, 719 (1972).
29. Rao U. R., Ananth A. G., Agrawal S. P. Characteristics of quiet as well as enhanced diurnal anisotropy of cosmic radiation. Planet. Space Sci., 20, 1799 (1972).
30. Sandstorm A. E. Cosmic ray physics, 286 p. (North Holland Publ. Comp., Amsterdam, 1965).
31. Shrivastava P. K. High speed solar wind streams and cosmic ray intensity variation. 28thInt. Cosmic Ray Conf., Tsukuba, 3731 (2003).
32. Subramanian G. Amplitude of diurnal anisotropy of cosmic ray intensity. J. Geophys. Res., 76 (4), 1093ó1096 (1971).
33. Subramanian G. In: J. Geophys. Res., 49, 34 (1971).
34. Venkatesan D., Badruddin B. Cosmic-ray intensity variations in the 3-dimensional heliosphere. Space Sci. Rev., 52, 121 ó 194 (1990).