In Memoriam

Götz Paschmann (1939-2023)

My long-term colleague and friend, Goetz Paschmann, passed away on 22 February this year at the age of 83. He was one of the leading scientists in the near-Earth plasma physics group at the Max Planck Institute for extraterrestrial Physics, MPE. He joined our institute in 1968 in order to perform his doctoral thesis research under the guidance of Reimar Lüst and Dieter Hovestadt. He analyzed data on auroral particles gained by Dick Sharp and Ed Shelley as Visiting Scientist at the Palo Alto Research Laboratory, USA, from 1968 to 1970. He obtained his doctoral degree from the Technical University Munich, Germany, in 1971. As staff member at the MPE from 1971 to 1978, he gained an international reputation for his work on the magnetospheric boundary layers with data from a novel instrument on the ESRO spacecraft HEOS 2 built by Helmut Rosenbauer at MPE.

In 1978, Goetz was Visiting Scientist at the Los Alamos National Laboratory (LANL), USA. With Sam Bame of LANL he shared the PI-ship of the plasma analyzers on the NASA missions, ISEE 1 and 2. With data from a magnetopause transit of the spacecraft, his team succeeded in verifying for the first time ever the working of the reconnection process in space. The subsequent Nature paper in 1979 was probably the most important publication of MPE in space physics. From 1978 onward, he was Senior Staff Member at MPE and Head of Space Plasma Physics. Subsequently, Goetz was PI on the ill-fated Firewheel mission in 1980 and of the plasma analyzer on AMPTEIRM, the spacecraft with which we succeeded in creating two artificial comets in 1984-85. One of his important discoveries with AMPTE, jointly with Wolfgang Baumjohann, was the identification of the flow bursts, which carry the energy liberated by reconnection in the magnetic tail towards the night-time magnetosphere generating substorms, spectacular auroral displays, and strong geomagnetic perturbations.

"One of his important discoveries was the identification of the flow bursts"

From 1999 to 2005, Goetz was Director at the International Space Science Institute (ISSI) in Bern, Switzerland, for six months per year, succeeding Bengt Hultqvist. During this period, he led the production of the book “Auroral Plasma Physics”, jointly with Stein Haaland and Rudolf Treumann, and with contributions from 32 European and US colleagues. It became the reference book in this field.

Goetz Paschmann was also one of the driving forces behind ESA’s Cluster mission. With strong international contributions, among others by Carl McIlwain, Jack Quinn, and Roy Torbert, he led the building and operation of the electron drift instrument, EDI. It made it possible, with help of an electron beam emitted from one side of the spacecraft and detected on the other side, to derive the magnitude of the magnetic field and the electric field with high precision from the delay and displacement of the beam after one gyroperiod. This instrument was the most complex product ever emerging from our group.

After his retirement in 2004, Goetz continued his research with unbroken intensity. Using data from the Magnetospheric Multi-Scale Mission (MMS), in close cooperation with a great many international colleagues, such as Bengt Sonnerup, Tai Phan, Stein Haaland, Jack Gosling, and Roy Torbert, he generated a strong output of papers on subjects such as discontinuities in the solar wind, reconnection, convection in the magnetosphere and the like. At MPE, he shared an office with Berndt Klecker and Manfred Scholer. In 2004, he was awarded an honorary doctor’s degree of the Institute of Geophysics of the Ludwig-Maximilians-Universität, Germany, for his important contributions to the external geophysics. In 1994 he became a Fellow of the American Geosciences Union (AGU) and a Fellow of the Royal Astronomical Society, London. In 2003, he received the Hannes Alfvén Medal of the European Geophysical Union (EGU) and, in the same year, he held the James Van Allen Lecture at the Fall AGU Meeting.

"He generated a strong output of papers on subjects such as discontinuities in the solar wind, reconnection, convection in the magnetosphere"

Goetz’ decease is a great loss for science and for the great number of friends he won in the course of his scientific career. We have been friends since his joining MPE. I enjoyed intensely working with him, exchanging ideas or solving problems. Our friendship included his wife, Karin, and the two growing families. Besides Karin, he leaves behind his daughter, Ulrike, his son, Andreas, and their respective spouses and children.

[by Gerhard Haerendel, former Director of MPE, Germany and former COSPAR President, 1994-2002]