The goal of GIRAFF is to study the processes responsible for creating the fastest optical variations observable within the aurora. This investigation focuses on two specific mechanisms of energy coupling, namely Electromagnetic Ion Cyclotron (EMIC) wave-particle interactions at low altitude (below 3000 km) and chorus wave modulation in the equatorial magnetosphere that can have significant impacts on the total energy flux of electrons precipitating from the magnetosphere to the ionosphere/thermosphere.  Therefore, to better understand the mechanisms of these interactions, this investigation targets two different, yet somewhat similar auroral phenomena, namely flickering and fast pulsating aurora, where these wave-particle interactions are manifested as modulations of the auroral luminosity, which typically occur at relatively high frequencies between a few Hz and 15 Hz or more. GIRAFF will accomplish the science goal by launching the two identical rockets through two different types of aurora using a suite of science instruments with previous sounding rocket heritage.


The main questions GIRAFF hopes to answer are:
1.            What are the precipitating electron spectra (energy, flux and temporal characteristics) responsible for creating flickering and fast pulsating aurora?
2.            What constraints can be placed on locating where the electromagnetic wave -particle interactions occur for flickering and fast pulsating aurora?
3.            To what extent do the spatial variations observed in the optical auroral emissions correspond to variations within the precipitating electron distributions?

The Principal Investigator is Dr. Michell/NASA Goddard Space Flight Center