(note: continuing with our series about barium related research in atmospheric science, we offer in part 3 an excerpt from from chapter 6, pages 179-180, of the informative book, "The Century of Space Science", by J. A. M. Bleeker, Johannes Geiss, M. Huber, Published 2001. part 2, part 1)
BIERMANN'S THEORY OF THE INTERACTION OF THE SOLAR WIND WITH THE IONIZED COMETARY TAILS
In 1950 Ludwig Biermann taught a course about comets at the Astronomical Observatory of the University of Gottingen. At that time, I was a PhD student attending these lectures.
Biermann was puzzled about why tails with ionized molecules always pointed away from the Sun, while tails consisting of non-ionized molecules and dust were curved toward the Sun. The latter form could be explained by the solar light pressure and the motion of the comets around the Sun.
However, explanations of the light pressure as a force to blow away the ionized tails failed by orders of magnitude. Biermann developed the theory that the corpuscular radiation of the Sun was responsible for the high acceleration observed in the ionized tails.
That the Sun sporadically emits a corpuscular radiation was known from the observed perturbation of the Earth's magnetic field. (image right of Earth's magnetic field, from physics.ubc.ca)
Not known at that time was that the Sun emits a corpuscular radiation continuously. This phenomenon was first detected by Russian spacecraft and by the U.S. satellite Explorer X and explained theoretically by Eugene Parker. (image left from climateaudit.org, click image for detail)
Biermann published his theory of the interaction of solar corpuscular radiation with the ionized cometary tails in two papers (1951, 1952).
In these, he demonstrated the close correlation of events in the tail of comet Whipple-Fedke with the registration of magnetic storms.
In a later paper (dedicated to Heinsenberg's 50th birthday) he showed that a similar correlation existed for the ionized tails of comet Halley in 1910. (image right model of Earth's magnetic declination, from geomag.usgs.gov)