Of men and instruments: The Norwegian Aurora Expedition to the Arctic, 1902–1903

ABSTRACTIn 1902, the Norwegian Professor Kristian Birkeland organised an expedition to the Arctic for studies of the aurora borealis, terrestrial magnetism and cirrus clouds. He established four stations at different locations—northern Norway, Iceland, Spitsbergen and Novaya Zemlya—all equipped with a similar set of scientific instruments. Using an extended concept of a scientific instrument, it is shown here that not only the instruments themselves, but also the external equipment, buildings and camp-facilities, as well as the manual work performed by the expedition members all played a role in obtaining the final results. Further, it is shown that Birkeland's efforts in organising and funding the expedition can be seen as an instrument-making operation.

Kristian Birkeland's pioneering investigations of geomagnetic disturbances

More than 100 years ago Kristian Birkeland (1967–1917) addressed questions that had vexed scientists for centuries. Why do auroras appear overhead while the Earth's magnetic field is disturbed? Are magnetic storms on Earth related to disturbances on the Sun? To answer these questions Birkeland devised terrella simulations, led coordinated campaigns in the Arctic wilderness, and then interpreted his results in the light of Maxwell's synthesis of laws governing electricity and magnetism. After analyzing thousands of magnetograms, he divided disturbances into 3 categories: 1. Polar elementary storms are auroral-latitude disturbances now called substorms. 2. Equatorial perturbations correspond to initial and main phases of magnetic storms. 3. Cyclo-median perturbations reflect enhanced solar-quiet currents on the dayside. He published the first two-cell pattern of electric currents in Earth's upper atmosphere, nearly 30 years before the ionosphere was identified as a separate entity. Birkeland's most enduring contribution toward understanding geomagnetic disturbances flowed from his recognition that field-aligned currents must connect the upper atmosphere with generators in distant space. The existence of field-aligned currents was vigorously debated among scientists for more than 50 years. Birkeland's conjecture profoundly affects present-day understanding of auroral phenomena and global electrodynamics. In 1896, four years after Lord Kelvin rejected suggestions that matter passes between the Sun and Earth, and two years before the electron was discovered, Birkeland proposed current carriers are "electric corpuscles from the Sun" and "the auroras are formed by corpuscular rays drawn in from space, and coming from the Sun". It can be reasonably argued that the year 1896 marks the founding of space plasma physics. Many of Birkeland's insights were rooted in observations made during his terrella experiments, the first attempts to simulate cosmic phenomena within a laboratory. Birkeland's ideas were often misinterpreted or dismissed, but were verified when technology advances allowed instrumented spacecraft to fly in space above the ionosphere.

Little Earth: A Solar-Planetary Investigation

The authors present Little Earth, the result of collaboration between artist Jo Joelson and the Radio and Space Plasma Physics Group at the University of Leicester. The project draws on the historical research of Kristian Birkeland and C.T.R. Wilson to examine how developments in technology have affected the relationships between artists and scientists in observing and representing the natural world. The principal output of the project was a multi-channel video work representing a fictional dialogue between Birkeland and Wilson, projected onto the faces of a sculptural form inspired by contemporary spacecraft design.