Daniel N. Baker’s contribution to our understanding of the Van Allen radiation belts through experiment, discovery, and interpretation of observations is without peer. He has made major scientific contributions across a wide range of topics in space plasma physics and taken a leading role in developing the nation’s space weather program, informing Congress and the public about the potential hazards to humankind of extreme space weather events. His expertise in experimental studies of energetic particle processes in space, their relationship to the radiation belts, and ensuing impacts on technical systems orbiting Earth has been amplified by his leadership at national and academic laboratories and in educating the next generation of space scientists.
Dan has led scientific investigations on numerous NASA missions, including the Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX) satellite, NASA’s first Small Explorer (SMEX) mission. His group provided a two–solar cycle baseline for the radiation belts and synoptic basis for interpreting the recent extreme solar minimum. Following community discussion of a potential Maunder Minimum, he demonstrated that a strong coronal mass ejection observed by NASA’s Solar and Heliospheric Observatory (SOHO) spacecraft could have caused an extreme “Carrington event”–magnitude geomagnetic storm had it struck Earth in 2012. He was investigator on the Student Nitric Oxide Explorer Mission, was a lead investigator on the Mercury Surface, Space Environment, Geochemistry and Ranging (MESSENGER) orbiter mission, and is now lead investigator on the flagship four-spacecraft Magnetosphere Multiscale Mission launched in 2015 to study magnetic reconnection, the process converting magnetic into particle kinetic energy at Earth, Sun, and stars. Dan, as principal investigator for the Relativistic Electron Proton Telescope on the Van Allen Probes twin spacecraft mission launched in 2012 to study the radiation belts, has published many of the major discoveries, from the third “storage ring” early in the mission to the “impenetrable barrier” to highly relativistic electron penetration deep into the inner magnetosphere.
In addition to his scholarship in top journals, Dan has unselfishly served the space research community in significant capacities. He held leadership positions at two national laboratories, Los Alamos and NASA Goddard Space Flight Center, and since 1994 has been the director of the Laboratory for Atmospheric and Space Physics at the University of Colorado. He served with great distinction as chair of the most recent National Academies’ decadal survey in heliophysics. Dan has continued to serve as a strong advocate for new scientific missions and strengthening our technological infrastructure through greater understanding of the potential extreme variability of the natural space environment.
—Mary K. Hudson, Dartmouth College, Hanover, N.H.; also at High Altitude Observatory, National Center for Atmospheric Research, Boulder, Colo.
![](/-/media/Feature/Common/Agu/Images/Publications/Journals/JGR-Space-Physics.jpg?h=1264&w=1255&hash=877065AF21B5280E6E223BBABF9EA0B0)
The present study uncovers the fine structures of magnetosonic waves by investigating the EFW waveforms measured by Van Allen Probes. We show that ...
![](/-/media/Feature/Common/Agu/Images/Publications/Journals/Geophysical-Research-Letters.jpg?h=1178&w=1180&hash=4880D968F0E3D877CB064FD2593561E9)
![](/-/media/Feature/Common/Agu/Images/Publications/Journals/JGR-Space-Physics.jpg?h=1264&w=1255&hash=877065AF21B5280E6E223BBABF9EA0B0)
![](/-/media/Feature/Common/Agu/Images/Publications/Journals/Geophysical-Research-Letters.jpg?h=1178&w=1180&hash=4880D968F0E3D877CB064FD2593561E9)
![](/-/media/Feature/Common/Agu/Images/Publications/Journals/JGR-Space-Physics.jpg?h=1264&w=1255&hash=877065AF21B5280E6E223BBABF9EA0B0)