Open Access Textbook on Van Allen Radiation Belts
FORESAIL Observations-Team leader Emilia Kilpua recently published a fully open access textbook titled Physics of Earth’s Radiation Belts: Theory and Observations with emeritus professor Hannu Koskinen. The space radiation environment surrounding the Earth is one of the key science focuses of FORESAIL and important factor affecting spacecraft lifetime. Funding to cover the publication expenses was received from the Finnish Society of Sciences and Letters and Magnus Ehrnrooth foundation.

Our planet is surrounded by doughnut shaped regions of high energy charged particles. These Van Allen radiation belts were found at the dawn of the space age, and they have puzzled scientists over six decades. They not only challenge our physical understanding but are a threat to satellites in orbit and can affect atmospheric chemistry.

A few weeks ago, it was time to pop champagne and raise a toast. The textbook Hannu Koskinen and I had been writing over the past three years on Earth’s radiation belts was finally published by Springer Astronomy.

Hannu got the idea of the book in 2016 when we both participated in a meeting held at the International Space Science Institute in Bern, Switzerland.  He asked me to join the project. We drafted the outline and started writing.

Timing for the book was perfect. NASA’s Van Allen Probes were launched in 2012 and they quickly revolutionized our knowledge of the belts. New observations and papers based on them were pouring in. They revealed the extreme variability and complexity of the belts, provided many surprises and allowed testing previous theories and creating new ones.

The writing turned out to be a formidable task, much harder than neither of us had expected. The number of studies related to belts is simply huge.  We did not want to write a review, but a textbook that provides readers of variable backgrounds fundamentals of physics and concepts related to belts while emphasizing close ties between observations and theory.

Another issue was the sheer complexity of physical processes governing the energetic electron dynamics in the belts. The radiation belt region is filled with various plasma waves that can accelerate and transport electrons and scatter them away from the belts. Different wave modes also work in a synergistic manner. This complexity is part of the charm of Van Allen belts and what captivated us.

We educated ourselves in Radiation Belt Journal Club meetings with other FORESAIL researchers. Hannu suggested this when we started writing the book. Since then, we have gathered every two weeks to review a paper while enjoying a cake the presenter must also offer.

We are now wiser and older, but even after writing this treatise the belts keep us intrigued. I could say this process taught me most so far during my career. Many phenomena and physical processes in the belts remain enigmatic and it is certain new surprises are to come.