A statistical study relating IPDPs to substorm onset

Intervals of Pulsations of Diminishing Periods (IPDPs) are a subtype of Electro-Magnetic Ion Cyclotron (EMIC) waves that are characterized by an increase in frequency over time. IPDPs can be triggered by proton injections into the plasmasphere during substorm onset, but while substorms can be a daily occurrence, IPDPs are significantly rarer. This peculiarity was noted in Hayashi et al. (1981), which simply concluded that IPDPs are not caused by every substorm related plasma injection. To address this I propose conducting a statistical study examining IPDPs associated with substorm onset, using the Auroral Electrojet (AE) index as a proxy to do so. The purpose of this would be to understand how frequently and under what conditions IPDPs are observed alongside substorm onset. We have much of the data in-house, and a preliminary analysis of a full years worth of data has already been analyzed by an undergraduate in the lab (Jeffrey Campbell). IPDPs have been identified both visually and through polarization analysis, and peaks and averages of the AE index have been recorded. To avoid confirmation bias, spectrogram data and the AE index were evaluated separately at different times. Criterion for the comparison has not yet been established.