Galactic CR in the Heliosphere according to NM data, 5. Comparison of results for solar minimum and maximum.
Abstract
On the basis of NM data on stations with different cut-off rigidities we found rigidity dependence of galactic cosmic ray long-term variation near the last solar minimum (sunspot numbers W40, period January 1994-January 1997). In the frame of the model of global cosmic ray modulation in the Heliosphere with taking into account time-lag of processes in the interplanetary space relative to processes on the Sun by using data on solar activity-cosmic ray hysteresis effects, we determine the dimension of modulation region, radial diffusion coefficient, cosmic ray intensity out of the Heliosphere, and residual cosmic ray modulation in dependence of primary cosmic ray particle rigidity with taking into account drift effects according to Burger and Potgieter (1999). We include in the consideration drift effects (as depending from the sign of solar polar magnetic field and determined by difference of total CR modulation at A>0 and A<0, and with amplitude dependent from the value of tilt angle between interplanetary neutral current sheet and equatorial plane). The amplitude of drifts in dependence of CR particle rigidity we use what was obtained in Dorman et al. (2002) from comparison of CR modulation in odd and even solar cycles. We estimate the dimension of modulation region (with taking into account the influence of nonlinear processes on the solar wind speed in the outer Heliosphere according to Le Roux and Fichtner, 1997), the radial diffusion coe fficient and transport path in radial direction as well as residual CR modulation in the minimum of solar activity in dependence of primary CR particle rigidity. We discuss these results in connection with obtained in Dorman et al. (2002) and compare with obtained in solar maximum. REFERENCES: Burger, R. A., and M. S. Potgieter, Proc. 26th Inter. Cosmic Ray Conf., 7, 13, 1999. Dorman, L.I., et al., Report on COSPAR_2002. Le Roux, J. A. and H. Fichtner, Ap. J, 477, L115, 1997.
- Publication:
-
34th COSPAR Scientific Assembly
- Pub Date:
- 2002
- Bibcode:
- 2002cosp...34E2921D