So what are these things? Well, it's in the name, they are an electromagnetic ion cyclotron wave... I know doesn't help. They are a wave that we see in both the electric and magnetic fields. They resonate with ions. When Ions are around in the magnetic field, they start moving in a circle around it. When the conditions are right, the particles moving around the field line can start growing these EMIC waves. As the waves grow, they can start scattering the particles as shown in the youtube video below from NASA. This of course then changes the conditions around the wave and ultimately the wave is turned off. It's a bit self defeating.
Now after all of this what did we find? We found that waves were more common during storms than not and that they happen more at noon and dusk than at midnight and dawn. Why does one care? We care because it helps us understand how much area is affected by these waves, and thus how much they will affect the radiation belts. This is important to know because it helps us better understand what types of space weather may impact satellites, communication, and radiation at aviation altitudes. There are of course a few steps in between this study and these applications, but it is all part of the processes.
One of my favorite parts of this paper though was the method. We picked this multi-epoch approach and that was quite novel at the time. But, it had one major failing. This was not the method used by others, so how could we compare our results to theirs. They had used different data sets than us, so were our results different because of the method used or because of the different data. In order to try to answer that question, we did a second small study where we used a similar method to the previous papers. Lo and behold we got the same results of them. What we had found was that our interpretation of what was going on was impacted by the method. Our new multi-epoch analysis allowed us to better understand what parts of the storm had the conditions where you might find an EMIC wave. This is sort of like saying we see that schools close when there is snow vs the schools close when there has just been a snow storm and there hasn't yet been time to clear the roads. It might not seem like a big difference but is important if you are predicting when schools will close in Minnesota. (But the first approach might be okay if trying to predict when schools will close in Georgia).
As my career has progressed, I have moved on to looking at a much wider set of space weather activities. But I have been fortunate enough to continue to work with EMIC waves from time to time. They really are a neat type of wave seen in our magnetosphere... My brother is right, I really am a nerd.