1. On the relative role of drift and convection-diffusion effects in the long-term CR variations on the basis of NM and satellite data
Lev Dorman (1, 2)
Israel Cosmic Ray and Space Weather Center, affiliated to Tel Aviv University, Technion, and Israel Space Agency
2. Cosmic Ray Department of IZMIRAN, Russian Academy of Sciences

2. CONTENTS
1. Hysteresis phenomenon and the model of CR global modulation in the frame of convection-diffusion mechanism
2. Even-odd cycle effect in CR and role of drifts for NM energies
3.CR propagation and modulation during solar cycle 22 on the basis of NM data
4. Main results for cycle 22
5. Diffusion time lag for small energy particles
6. Convection-diffusion modulation for small energy galactic CR particles
7. Small energy CR long-term variation caused by drifts
8. The satellite proton data and their corrections
9. Correlations for proton satellite data
10. The GOES satellite alpha-particle data from January 1986 to May 2000
11. Conclusion: Relative role of drift in dependence of CR energy (NM and satellite data)

3. 1. Hysteresis phenomenon and the model of CR global modulation in the frame of convection-diffusion mechanism

6. 2. Even-odd cycle effect in CR and role of drifts for NM energies

9. 3.CR propagation and modulation during solar cycle 22 on the basis of NM data

11. 4. Main results for cycle 22

12. 5. Diffusion time lag for small energy particles

15. 6. Convection-diffusion modulation for small energy galactic CR particles

16. 7. Small energy CR long-term variation caused by drifts
Expected drift modulations for R = 3, 1, and 0.3 GV relative to the intensity out of the Heliosphere, in dependence of sunspot number W and derived from Burger and Potgieter (1999)

18. 8. The satellite proton data and their corrections

22. 9. Correlations for proton satellite data

24. 10. The GOES satellite alpha-particle data from January 1986 to May 2000

28. 11. Conclusion: Relative role of drift in dependence of CR energy (NM and satellite data)
With an increasing effective CR primary particle rigidity from 1015 GV (Climax NM and Kiel NM) up to 3540 GV (Huancayo/Haleakala NM) are decreased both the amplitude of drift effect (from about 1.5% to about 0.15%) and time-lag (from about 13 av. months to about 10 av. months). It means that in cycle 22, for the total long term modulation of CR with rigidity GV, the relative role of the drift mechanism was 4x1.5%/25%  1/4 and the convection-diffusion mechanism about 3/4 (we take into account that observed total 11-year variation in Climax and Kiel NM is 25%, and the total change of CR intensity owed to drift effects is about 4 times more than the amplitude ); for rigidity GV these values were 4x0.15%/7%  1/10 for the drift mechanism, and about 9/10 for the convection-diffusion mechanism. If we assume that the average velocity of the solar wind in the modulation region was about the same as the observed average velocity near the Earth’s orbit in : u = 7.73 AU/(average month), the estimated dimension of modulation region in cycle 22 will be ~ 100 AU

29. For protons with energy more than 100 MeV from IMP and GOES data we obtained drift amplitude about 0.1=10%, what gives for total drift modulation about 40%. The total variation for protons ln(11Mcor) from 9.2 up to 8.0 was about 120%. It means that the relative role of drift modulation is 1/3 and convection-diffusion 2/3.
For alpha-particles with energy MeV (effective rigidity 0.9 GV) from GOES data we obtained drift amplitude 0.087=8.7%, what gives for total drift modulation about 35%. The total variation for alpha-particles ln(11Mcor) from up to -7.0 was about 75%. It means that the relative role of drift modulation is 1/2 and convection-diffusion also 1/2.
So, the relative role of drift modulation decreased from about 50% for CR with effective rigidity 0.9 GV up to 25% at GV, and then up to 10% for GV; correspondingly the relative role of convection-diffusion modulation increased from 50% for CR with effective rigidity 0.9 GV up to 75% at GV, and then up to 90% for GV.