My article in Nature, Ephemeral Third Ring of Radiation Makes Appearance Around Earth, discusses how twin spacecraft studying the Van Allen radiation belt overturned a fifty year old model: Instead of seeing two rings of high-energy particles circling the Earth, an unexpected third ring has been found.
From the article:
…telescopes on the probes revealed the emergence of an additional, narrow belt of charged particles sandwiched between the inner ring and a now highly eroded outer ring. “It was so unexpected that we thought there was something wrong with the instrument,” says Daniel Baker, a space physicist at the University of Colorado in Boulder.
The findings, which are reported today in Science, demonstrate that solar outbursts are indeed a strong driving force behind the structure of the belts and that similar activity might be common, especially now, near the peak of the 11-year solar cycle, Baker says. Nonetheless, he adds, details about the dramatic reshaping of the outer belt and the location of the month-long middle ring cannot be explained by current theory.