When you are completing a PhD you typically end up dedicating more years than one would like to admit learning about, studying, discovering, and obsessing over a very small section of the edge of our understanding. The topic of my thesis was occurrence and plasma characteristics of Electromagnetic Ion Cyclotron (EMIC) waves on the CRRES mission during different geomagnetic conditions. Notice it wasn't EMIC waves in general, it was EMIC waves on this one satellite. It wasn't wave properties, or generation mechanisms, propagation of or a whole host of other important factors for EMIC waves, it was one small specific topic... But by the end of my PhD I was the expert on EMIC waves observed on CRRES and their occurrence during different types of magnetospheric weather. Granted this did make me one of the experts on EMIC waves in general, but that's not saying much when there are perhaps only a hand full of those in the world anyway.
So this paper goes back to much of the work that went into the thesis. It for the most part summarized all of the results into one big picture. From the first glance, this looks like and incredibly boring paper filled with lots of statistics and that's about it (there are 55 tables in the supporting information). But I think it's probably one of the more important papers that I've written. I say that because it's the start of building an empirical model of EMIC wave parameters and local plasma characteristics which are important for wave-particle dynamics. In most current global magnetospheric models, these and many other wave types are unable to be self consistently (occurs from just the equations used in the computer model) included. What does that mean... Well when we try to model the magnetosphere, the space is so large, our grid and time steps have to be relatively large. Any physics, any activity that takes place on shorter time scales, or smaller spatial scales can not be resolved. If it can't be resolved then we can't include it.
Think of taking a landscape photo. Like this one of BARREL.
Now you may ask "why can't we just make our models have smaller time and space steps?" This is often my question to modelers. They assure me, and once you look at it you can easily see yourself, that if we were to do that, the computations would take months, years, even decades in some instances instead of the days and weeks the runs take now. There are some modelers who do increase the grid and time steps in order to model EMIC and other waves. But they do this in very small regions, so their models aren't global. We keep working on ways to improve our models, but it will be quiet awhile before we can improve them to the point of having EMIC waves in there self consistently (not having to force their occurrence but let them grow and die naturally in the model itself). Really we need an advancement of computers themselves...
So why should you care about this work?
This paper provides a nice set of look up tables for EMIC waves and plasma parameters by location around the magnetosphere (in L and MLT) for different geomagnetic conditions, quiet time, storms in general, then pre-storm, main phase, and recovery phases.
Perhaps more importantly however, we showed that only sorting EMIC waves by Dst/Sym-H (and index used to define storms), AE (an index typically used to define substorm occurrences), or Kp (an index often thought to represent convection) does a very poor job. We show some statistics and discuss why this may be. We believe that more statistical studies need to consider the geomagnetic activity instead of a single index as the conditions in the magnetosphere can be very very different.
If you are a member of the public:
Much of our technology can be affected by space weather. Sometimes we can harden this technology, so in other words find ways to make it more resilient to the space weather. Other times we can't and need to be prepared to either protect it by turning it off, or flying around the region affected. This paper not only helps us define the region of the magnetosphere, and thus the upper atmosphere potentially affected by EMIC waves during different space weather events, but it also is a start for us finding ways to include it into our space weather forecasting!
So it may not seem like a good read (unless you have insomnia and need something to put yourself to sleep), but it will hopefully one day lead to improvements our space weather forecasting! Or some other study may come out that does a better job of characterizing the statistics and that will be used instead. But that's the nature of science, progress is always made in fits and starts. Currently there are no other papers with this type of statistics provided, but now that I've published this for CRRES, someone may go and do this for Van Allen or one of the other satellites before modelers start using my results. Modelers then may find that they prefer to use the Van Allen statistics instead of the ones I've presented. But that's the way science gets done. One small step at a time.