An interplanetary scintillation activity index

Using interplanetary scintillation (IPS) data obtained from the Cambridge 81.5 MHz array, we have developed an activity index in which we identify (i) discrete structures, most likely relating to transient density enhancements, and (ii) periodic activity, relating to co-rotating interplanetary structure. We find significant, yet weak correlations between the index and geomagnetic activity. Our results suggest that the persuit of such an index could result in a valuable tool for the prediction of geomagnetic events and highlight several potential future developments