Richard Horne

The 2025 Julius Bartels Medal is awarded to Richard Horne for outstanding work on understanding the acceleration and transport processes of charged particles in the inner magnetosphere, the formation of the radiation belts and their space weather effects.

Richard Horne is a world-leading researcher in the field of wave-particle interaction in the Earth’s s magnetic field and space plasma environment as well as that of other planets in the solar system. He has provided fundamental contributions to the physical processes leading to acceleration and transport of relativistic electrons in the Earth’s radiation belt, known as the Van Allen Belt.

Horne examined all major types of electromagnetic and electrostatic plasma waves in the Earth’s magnetosphere and discovered that the so-called chorus wave can accelerate electrons to relativistic energies, reaching almost the speed of light. Horne’s theory for local wave acceleration has replaced the radial diffusion paradigm as the dominant acceleration mechanism. The model based on local wave-particle interaction has been successfully applied to other planets of the solar system, such as Jupiter and Saturn despite the very different environments to that of the Earth and has been supported by measurements from recent space missions such as Cassini and Juno.

Horne’s modelling results on the formation of the outer radiation belts that surround the Earth have motivated the NASA Van Allen Probes mission, which further confirmed the wave-particle interaction concept. Richard Horne has published more than 250 papers in refereed journals. His core publications in 1998 and 2005, both as first author, have been cited more than 500 times as the standard reference on the electron acceleration processes.

Horne has also been very active in pushing the wider international community towards applied research required to support the operational needs of space weather services and industry. In this respect he led the EU SPACECAST project to develop a space weather forecasting system for satellites and the EU SPACESTORM project. His work has led to revised hazard assessments for the UK and achieved world-wide importance. Beyond that, Richard Horne has inspired the careers of numerous young researchers through his outstanding supervision.

In summary, Horne is one of the founders in the field of space science and has left a deep scientific and educational impact in the space physics and space weather community. These outstanding achievements make him an ideal recipient of the EGU's 2025 Julius Bartels Medal for solar-terrestrial sciences.