The 2023 Julius Bartels Medal is awarded to Hermann Opgenoorth for his exceptional contributions to substorms and space weather research, and his strong leadership in international collaboration.
Hermann Opgenoorth has been a prominent figure in the solar-planetary communities since the 1970s and continues to be a driving force. As of 2019 he has been Professor Emeritus in the Physics Department at University of Umeå in Sweden. During his long career he has worked in many different capacities, including Head of the Solar Terrestrial Physics research programme at the Swedish Institute for Space Physics in Uppsala, Head of the Solar System Missions Division of the European Space Agency, and Discipline Scientist at the International Space Science Institute. His wide range of research interests have covered areas such as the magnetosphere, ionosphere, and Mars – solar wind.
Opgenoorth has been the prime motivator for the expanding ability of many spacecraft missions (e.g., Cluster, SWARM) and ground-based observatories (e.g., EISCAT radar on Svalbard, the MIRACLE network of magnetometers, cameras, and riometers across Scandinavia, and the Svalbard extension of SuperDARN). He is specifically well-known for his advocacy for coordinated measurements between spacecraft and the ground. Many of his scientific accomplishments have been made possible by applying this approach, for example, he performed ground-breaking coordinated measurements between the Viking spacecraft and ground observatories, especially the EISCAT radar system. Examples of other important scientific research results obtained during his career include, among others, shedding light on the connection between ionospheric and magnetospheric phenomena, exploiting ground magnetometers to understand the three phases of auroral substorms, and obtaining a new understanding of the interaction of the ionosphere with crustal magnetic anomalies on Mars. Most recently he has focussed on explaining the sudden, violent changes in Earth’s magnetic field, produced during geomagnetic storms. Opgenoorth’s work has resulted in more than 200 referred publications in science and policy, and he is frequently invited to give presentations at international conferences.
In the spirit of international collaboration Opgenoorth’s efforts in encouraging people to work together across the globe is well-recognised in the solar-terrestrial communities. He was key in establishing the Mars Upper Atmosphere Network, an international scientific group of scientists dedicated to multi-instrument investigation of the Mars-solar wind interaction. Specifically, his participation in the foundation, original formulation and realisation of the International Living With a Star programme stands out as a beacon of light. This programme has been crucial for the scientific community to better understand the ultimate driver of space weather, the Sun, and how it and the space environment affects life and society. Indeed, space weather affects the whole Earth and Opgenoorth has been instrumental in uniting the world to work together on this inter-disciplinary subject.
The combination of Opgenoorth’s unique scientific research accomplishments during his exceptional career and his keenness for fostering international collaborations around space research makes him a very worthy recipient of the 2023 Julius Bartels Medal.