Kletzing's research focused on making in situ measurements of the plasma environment of the Earth's magnetosphere. Within the magnetosphere, his primary research interest was auroral physics and magnetosphere-ionosphere coupling processes. Much of his work concentrated on measurements of the electrons and ions in this region. These measurements are made both by satellites and small, sub-orbital rockets known as sounding rockets. Several of these sounding rocket flights have been over active aurora. He was interested in understanding interactions between waves and particles to understand how energy is exchanged between electric and magnetic fields and the kinetic energy of particles.
TRACERS
Kletzing was the principal investigator for the Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites (TRACERS) and a $115 million contract award from NASA, announced in June 2019, the largest single award in UI history.
Where, how, and why the solar wind couples to near-Earth space is a major unresolved scientific question at the heart of the TRACERS mission. With its two satellites traveling in tandem, TRACERS will take us a long way toward answering this and related questions. TRACERS overarching goal is connecting the magnetospheric cusp to the magnetopause - discovering how spatial or temporal variations in magnetic reconnection drive cusp dynamics. To address the overarching goal, TRACERS has three major scientific objectives
- Determine whether magnetopause reconnection is primarily spatially or temporally variable for a range of solar wind conditions.
- For temporally varying reconnection, determine how the reconnection rate evolves.
- Determine to what extent dynamic structures in the cusp are associated with temporal versus spatial reconnection.
Following Kletzing's death, David Miles, associate professor of Physics and Astronomy, became the principal investigator. Launch date is scheduled for April 2025.
EMFISIS/Van Allen Probes
He was also interested in the wave-particle interactions that take place in the Earth's Van Allen radiation belts. He was the Principal Investigator for the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) on NASA's twin spacecraft Van Allen Probes (formerly RBSP) launched August 30, 2012. The investigation concentrated on the waves in the radiation belts such as chorus, plasmaspheric hiss, magnetosonic equatorial noise, and EMIC waves. The suite also provided the DC magnetic field measurements for the mission. These measurements were some of the most highly resolved ever made in the radiation belts.
CHARM-2 and CAPER Sounding Rockets
Kletzing developed new techniques for measuring wave-particle correlations to further the understanding of wave-particle interactions. These interactions can occur in MHz frequencies, a challenging experimental problem, but one for which there are several possibilities for improving the current instrumentation. A rocket flight in the Winter of 2002 investigated these wave-particle correlations and we are currently analyzing the data from the flight. Another rocket flight in the Winter of 2003 investigated particles and waves above the Langmuir frequency. A wave-particle correlator flew on the CHARM-2 rocket in the Winter of 2010. This correlator went into the Earth's cusp region in 2014 on the CAPER sounding rocket mission.
Hydra Instrument
Extending outward from the auroral zone, there was electron and ion data from the Hydra instrument on the Polar satellite launched in February 1996. By analyzing the particle data from these missions (along with electric and magnetic field data taken at the same time), the characteristics of the processes that create the aurora can be inferred. Kletzing examined particle data for times when the Polar satellite was at high altitude in the northern auroral zone. The satellite was at a sufficiently high altitude that one can be certain that it is above the region in which auroral electrons are accelerated. This allows us to probe the source populations for the aurora with good resolution. He worked on correlation studies to determine which (if any) solar wind parameters are correlated with the characteristic energy and density of the auroral source population.
Freja
Kletzing was involved in a new technique to measure electric fields in space using electron beams. An experiment using this technique was flown on a German-Swedish satellite called Freja which was launched in October of 1992 from China. The focus of this mission was also auroral physics and demonstrated that this new technique worked quite well. The technique allowed a full vector determination of the electric field perpendicular to the background magnetic field. This was not always possible with other techniques and the new method complimented existing techniques. Since the method was validated, Kleting and his team used this data to better understand auroral electrodynamics.
Equator-S
Another implementation of this technique was on the Equator-S satellite launched in December 1997. Originally this experiment was to be flown on the four Cluster spacecraft. Unfortunately, these spacecraft were destroyed when their launch vehicle (the Ariane 5) exploded shortly after launch. Happily, both NASA and the European Space Agency decided to rebuild all four spacecraft (called Cluster-II) and they were successfully launched in August 2000. This version was substantially more complicated than the Freja version but allowed the determination of the electric field in regions where other techniques failed.