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  Deceleration Potential

The so-called deceleration potential is a cosmic ray modulation parameter deduced from space observations of the abundance variation of the different species in function of the solar cycle epoch. It is defined in Badhwar and O'Neill (1996). The parameter could be deduced either from the sunspot index or from Climax neutron monitor output, using simple linear formulae depending upon the phase of the solar cycle. A constant delay between solar activity and cosmic ray modulation is used. The deceleration potential parameter is used for example as input of galactic cosmic ray dose calculation with the model SIEVERT.

Ref. Badhwar G.D.and ONeill P.M.: 1996, Adv. Space Research, 17, (2)7-(2)17.

The deceleration potential is computed from estimated Climax NM counts (using a linear regression between Kerguelen NM output and Climax NM output). Blue bars are deduced from observed outputs and red ones from predicted values. Since a constant delay of 3 months exists between deceleration potential and NM counts (smoothed over 12 months), predicted values start 3 months before the month when the prediction was made.