Kristian Birkeland Astrophysics and Space Science Library

Home , Kristian Birkeland, Olaf Devik, Sam Eyde, Torahiko Terada

KRISTIAN BIRKELAND ASTROPHYSICS AND SPACE SCIENCE LIBRARY

VOLUME 325

EDITORIALBOARD Chairman W.B. BURTON, National Astronomy Observatory,Charlottesville, Virginia, U.S.A. ([email protected]);University of Leiden, The Netherlands ([email protected])

Executive Committe J. M. E. KUIJPERS, Faculty of Science, Nijmegen, The Netherlands E. P.J. VAN DEN HEUVEL, Astronomical Institute, University of Amsterdam, The Netherlands H. VAN DER LAAN, Astronomical Institute, University of Utrecht, The Netherlands

MEMBERS I. APPENZELLER, Landessternwarte Heidelberg-K¨Konigstuhl,¨ Germany J. N. BAHCALL, The Institute for Advanced Study, Princeton, U.S.A. F. BERTOLA, Universit´tad´ iPPadova, Italy J. P. CASSINELLI, University of Wisconsin, Madison, U.S.A. C.J.CESSARSKY, Centre d’Etudes de Saclay, Gif-sur-Yvette Cedex, France O. ENGVOLD, Institute of Theoretical Astrophysics, University of Oslo, Norway R.MCCRAY, University of Colorado, JILA, Boulder, U.S.A. P. G. MURDIN, Institute of Astronomy Cambridge, U.K. F. PACINI, Istituto Astronomia Arcetri, Firenze, Italy V. RADHKRISHNAN, Raman Research Institute, Banglore, India K. SATO, School of Science, The University of Tokyo, Japan F. H. SHU, University of California, Berkeley, U.S.A. B. V. SOMOV, Astronomical Institute, Moscow State University, Russia R. A. SUNYAEV, Space Research Institute, Moscow, Russia Y. TAANAKA, Institute of Space & Astronautical Science, Kanagawa, Japan S. TREMAINE, CITA, Princeton University, U.S.A. N.O. WEISS, University of Cambridge, U.K. KRISTIAN BIRKELAND

The First Space Scientist

by ALV E GELAND University of Oslo, Norway

and

WILLIAM J.BURKE Air Force Research Laboratory, USA A C.I.P. Catalogue record for this book is available from the Library of Congress.

ISBN-10 1-4020-3293-5 (HB) Springer Dordrecht, Berlin, Heidelberg,NewYork ISBN-10 1-4020-3294-3 (e-book) Springer Dordrecht, Berlin, Heidelberg, New York ISBN-13 978-1-4020-3293-6 (HB) Springer Dordrecht, Berlin, Heidelberg, New York ISBN-13 978-1-4020-3294-3 (e-book) Springer Dordrecht, Berlin, Heidelberg,NewYork

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Caption to Front Plate: Professor Kristian Birkeland withhis left hand resting on an electric discharge tube of the high-voltage device used in 1896 to generate artiﬁcial auroral displaysin his laboratory. Asta Nørregaard (1853–1933) painted this portrait in 1906 (100 × 83 cm).

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Printedinthe Netherlands. CONTENTS

Preface ...... ix Introduction ...... 1 Part I: Background and Education ...... 11 1At the 19th Century’s E n d...... 11 1.1 Union of Norway and Sweden ...... 11 1.2 The Royal Frederik University in Kristiania ...... 12 1.3 Early Investigation of the Aurora and Geomagnetism ...... 13 2 ANew Abel ...... 17 2.1 The Birkeland Family ...... 17 2.2 High School and University Education ...... 19 2.3 Postgraduate Research in France, Switzerland, and Germany .... 22 Part II: Geomagnetic and Solar System Research ...... 27 3 Aurora inaVacuum Chamber ...... 27 3.1 Electromagnetic Wave Experiments ...... 27 3.2 EarlyLaboratory Simulations ...... 28 3.3 Birkeland’s O ffices and Laboratories at theUniversity ...... 34 3.4 TerrellaasAnodeExperiments ...... 36 4 The Norwegian Auroral Expeditions ...... 45 4.1 Birkeland’s First Expeditions ...... 45 4.2 Arctic Expedition of 1902–1903 ...... 57 4.2.1 The Four Stations...... 61 4.2.2 Birkeland’s Main Research Contribution ...... 66 4.3 Classification of Geomagnetic Disturbances ...... 70 4.3.1 Polar Elementary Storms ...... 72 4.3.2 Equatorial Perturbations...... 73 4.3.3 Cyclo-Median Perturbations ...... 74 4.3.4 Field-Aligned Currents in Space ...... 75 4.4 The Permanent Station at Haldde Mountain ...... 77 4.5 Controversies with the British School ...... 80 5 The Universe in a Vacuum Chamber ...... 87 5.1 Terrella as Cathode Experiments ...... 87 5.2 Sunspots and the Solar Magnetic Field ...... 87 5.3 Comet Tails ...... 90 5.4 Saturn’s Rings...... 93 5.5 Zodiacal Light...... 94 5.6 Conflicts with Carl Størmer...... 98 vi CONTENTS

Part III: Technology and Applied Physics ...... 101 6 Fast Switches and Electromagnetic Cannons ...... 101 7 Inas LittleasFourYears...... 109 7.1 Plasma Torch and Nitrogen Fixation ...... 109 7.2 Foundation of Norsk Hydro ...... 115 7.3 Conﬂict with Sam Eyde...... 120 7.4 Marcus Wallenberg ...... 123 7.5 Other Technical Applications...... 125 7.5.1 X-Rays ...... 126 7.5.2 Atomic Energy ...... 126 7.5.3 Rocket Propulsion ...... 128 7.5.4 Radiowave Propagation ...... 128 7.5.5 Production of Margarine ...... 129 7.5.6 Hearing Aid ...... 129 7.5.7 Cod Caviar ...... 130 7.5.8 RadiationTreatment...... 130

Part IV: Birkeland the Man ...... 131 8As Seen in His Own time ...... 131 8.1 Teacher and Experimenter ...... 132 8.2 Birkeland as a Popular Author ...... 135 8.3 Positions and Honors ...... 137 8.4 Nominations for theNobel Prize ...... 138 8.4.1 Nobel Prize inChemistry ...... 139 8.4.2 Nobel Prize inPhysics...... 140 9 Consummatus in brevi, explevit tempora multa ...... 141 9.1 Birkeland’s Health...... 141 9.2 Marriage and Divorce ...... 143 9.3 Sojourn in Egypt ...... 145 9.4 DeathinTokyo...... 148 9.5 Many Friends ...... 156 9.6 Birkeland’s Will...... 162

Part V: Birkeland’s Heritage ...... 165 10 From Small Acorns...... 165 10.1 Science Education in Norway ...... 166 10.2 Inﬂuence on Solar-Terrestrial Research...... 167 11 In Memoriam ...... 175 11.1KristianBirkeland Research Fund ...... 175 11.2 Birkeland Symposium...... 176 CONTENTS vii

11.3 Birkeland Lecture Series ...... 176 11.4 The Norwegian 200 Kroner Banknote ...... 179 Appendix 1 Birkeland’s Scientiﬁc Publications ...... 181 Appendix 2 Archives and Unpublished Sources ...... 189 Olaf Devik’s Personal Archive ...... 189 The Birkeland-Eyde Industrial Museum at Notodden...... 189 Norwegian Technical Museum in Oslo...... 190 The National Library Archive ...... 191 Norsk Hydro Archive ...... 191 Sam Eyde Archive ...... 191 Norwegian Storting Archives ...... 192 University of Oslo, Central Administration...... 192 Stockholm Enskilda Banken Archives ...... 192 Norwegian Academy of Science and Letters Archive ...... 192 Printed Sources from Norwegian Newspapers and Journals ...... 192 Biographies...... 194 Appendix 3 Patents ...... 195 Appendix 4 Letters ...... 201 Letter: Birkeland to Kaja Geemuyden ...... 201 Extracts from Terada’s Diary Concerning Kristian Birkeland in May–June 1917 ...... 203 Letter: TeradatoBirkeland(written in English)...... 205 Letter: TeradatoBirkeland(written in English)...... 206 Letter: NagaokatoBirkeland(written in English)...... 207 Letter: TeradatoBirkeland(written in English)...... 208 Letter: NagaokatoBirkeland(written in English)...... 209 Letter: GerdaThomsen to Karl Devik ...... 210 Letter: Eriksen to Birkeland ...... 213 Bibliography ...... 215 Index ...... 219 PREFACE

Thisscientific biographyof Kristian Birkeland(1867–1917) was written to bring the story of a Norwegian nationalhero to the attention of the English- speaking world.Birkeland’s heroic stature was established not on a field of military battle, but inthe bitter cold of theArticwilderness as he soughtto answer basic questions about how the Sun controlled northern lights and magnetic storms. He was also a father of Norsk Hydro one of Norway’s largest industries. Birkelanddiedbefore reaching the age of 50. Because Birkeland never kept a diary, documentedinformation about his family and private life is sparse. Before he died, Olaf Devik, the last of Birke- land’s c lose friends, gave a long interview and graciously transferredhis personal archive to A.E. Birkeland’s 82 scientific papers and three book-length publications map the progress ofhis investigations. We are gratefulfor the access granted to review the contents of many different archives. We greatly benefited from discussions with Professors Leiv Harang and Hannes Alfvén as well as members of the Norsk Hydro staff. We are very grateful to Profes- sor Naoshi Fukushima for translating and making availabletousBirkeland- related segments of Torahiko Terada’s diary. A.E. would also liketothank Espen Trondsen (University of Oslo) for computer assistance and Mrs L. Hedlund for languageadvice. We also extend special thanks to the staffs at The Norwegian Technical Museum, the Alta Museum responsible for the Haldde Observatory, and to the Birkeland-Eyde Industrial Museum at Notodden for providing useful illustra- tions. The authors express our special thanks to Ms Louise C. Gentile of Boston College Institute for Scientific Research for proofreading and editing our manuscript. This book would have been impossible to write without the constant encour- agement of our families, professional colleagues, and friends. Our gratitude extends to all who made this book possible.

Alv Egeland William J. Burke INTRODUCTION: TEMPORA MUTANTETNOS CUM ILLIS MUTAMUR

Our lives pass within confines that are briefintime andlimitedin range. Miracles of modern medicine prolong our days; modern means of communica- tion and transportation extend our reach across theglobe. Still we know limits. Personalinfluence is restrictedin duration andlocality. Yet there are people, Mozart comes to mind,whose contributions to collective human experience extendbeyond their prescribed times and places. We place before readers of this book, a synopsisof the lifeand contributions of such a man, Olaf Kristian Bernhard Birkeland, a Professor of Physics at TheRoyal Frederik University inKristiania,1 the capital of Norway, near the beginning of the 20th century. Our subtitle The First Space Scientist, places Birkeland’s life in the context of space exploration, half a century before “Sputnik” and “Apollo” entered our vocabularies. Over the course of the 20th century “space” evolved in the public con- sciousness from the captivating science fiction of Jules Verne (1828–1905) to a practical reality that touches innumerable aspects of modern living. We plan our activities around weather forecasts based on images from satellites hovering about 36,000 kilometers above the Earth’ssurface. How did this transformation come about? While it represents a triumph of rocket technology, much more is involved. Scientists had to devise and miniaturize electronic devices. This required the development of new materials that could withstand and operate in the harsh radiation environments of space. Industry had to create new management and quality assurance skills to meet schedules of unprecedented complexity. Every single mechanical and electronic component has to work within exacting specifications. Once launched, repair services are not available to replace failed components on a 100 million dollar spacecraft. The extraordinarily high cost of entry to space requires national and international investments and visions of future possibilities. The critical alliances among science, government, and industry needed to understand and operate in space were simplyunimaginable as the 20th century began. Atthetime scientists constituted a very small percentage of the total population. The vast majority of these were either associated with universities or inde- pendentlywealthy. Of the former, teaching responsibilities usually outweighed

1 In 1925, Norway’s capital reverted to Oslo, its name before the devastating fire in 1624. King Kristian IV of Denmark rebuilttheregion and renamed thecity. For 300 years, thecity was called Christiania, but during the last period was spelled Kristiania, as usedhere. 2 INTRODUCTION research opportunities. Still progress was made. As the 19th century concluded, practical implications of a newly discovered unity underlying electrical and magnetic phenomena were beinggrasped. Understanding, controlling, and utilizing the new world of electromagnetism challenged the contemporary imagination. Scientists distinguish between phenomena in laboratory experiments and in nature. Laboratory investigators control experimental environments exact- ingly to test theoretical understanding and to identify new interactions. At the other extreme, astrophysicists can only measure the effects of natural forces that lie light years beyond human control and try to interpret observations in the light of known physical laws. Much of Birkeland’sstory concerns hard won observations and bold interpretations of the natural interactions between the Sun and the Earth’s magnetic field that produce auroral displays and geomagnetic storms. Birkeland distinguished himself from contemporary investigators though laboratory simulations of natural electrical phenomena. Far ahead of his time, Birkeland’s prophetic concepts about the electric particles and currents controlling the physics of space passed into decades of eclipse before re- emerging in the 1970s. Throughout the years of eclipse, Birkeland’s reputation remained strong in Scandinavia, although heated debates raged concerning the validity ofhis speculations about space. Even inprinciple, no resolution could be foundbefore spacecraft probed altitudes above 100 kilometers. Birkeland’s reputation survived andflourishedbecause he was the first to forge alliances between science and the Norwegian government to investigate space, andbetween science andinternationalindustry to resolve an emerging crisis in feeding the growing global population. Olaf Kristian Bernhard Birkeland was born inKristiania on December 13, 1867 anddiedinTokyo on June 15, 1917. Althoughhis birth certificate reads“Christian”, as an adult he used only his second name, whichhe spelled “Kristian”. In publications after 1898, hesimplyreferred to himself as Kr. Birkeland.Birkeland’s life spans a watershed period when insights about elec- tricity and magnetism, codifiedby Maxwell inthemid-19th century, evolved from theoretical curiosities to become the basis for electronic technology and eventually for our understanding of the geospace environment. Friendsand colleagues universally recognized Birkeland asagifted man with awonderfully inventive mind that bubbled withideas and soughttoinves- tigate every aspect of thephysical sciences. In June 1890, Birkeland completed university studies inphysics, graduating youngest in hisclass with the highest grades. In January 1893, he was awarded a universitetsstipendiat, equivalent to a Research Assistantship, at theUniversity of Kristiania. Much ofhis early research was conductedin France, Switzerland,and Germanybetween January 1893 and August 1895. During this period, Birkeland published two theoretical INTRODUCTION 3 papers that drew wide attention. His mathematical training in Norway provided a superb foundation for developing the first general solution of Maxwell’sequa- tions. He continued to investigate the properties of electromagnetic waves in conductors and wave propagation through space. At the age of 28, he was elected to be a member of the Norwegian Academy for Science and Letters. In the Academy’s150-years history, only the famous Arctic explorer and oceanographer Fridtjof Nansen (1861–1930) was elected at a younger age. In October 1898, Birkeland was called by King Oscar II of Sweden to be senior Professor of Physics at the University of Kristiania. At that time, he was the youngest professor on the faculty. Because he looked younger than his age, for several years he was called “the boy professor”. In 1906, he was elected a fellow at the Faraday Society of London and in 1908 received an hon- orary doctorate, Doktor Ingenieur Honoris Causa, fromthe DresdenTechnical University in Germany. Birkeland married Ida Augusta Charlotte Hammer, who was four years his senior, in May 1905. She was a teacher of cooking at a girl’s school near Kristiania. They had no children and the marriage was not happy. They formally divorced in January 1911, after nearly two years of separation. While Professor of Physics at The Royal Frederik University in Kristia- nia (1898–1917),Birkelandlaid foundations for our current understanding of geomagnetism and polar auroras. In 1901, Birkelandinitiated a new set of laboratory simulations that hecalled Terrella Experiments.He hoped to prove incontrovertiblythe correctness ofhistheoreticalinterpretation of auroral and geomagnetic disturbances. For the first time cosmicphenomena were scaled and simulatedinalaboratory. His terrella experiments were at once simpleandin- genious. His largest chamber was a full cubic meter involume. He fully believed that the laboratory simulations confirmedhisunderstanding of auroras. They opened new paths suggesting how electromagnetic forces might operate inthe solar system. Birkeland’s laboratory simulations were brilliant successes that allowedhimtoargueby analogy about the causes of auroras and geomagnetic disturbances. In 1899, Birkelandbuiltthe first permanent auroral observatory in northern Norway atop a 900-meter mountain. He conducted three auroral and geomagnetic expeditions between 1897 and 1903. Of these, his four-station polar expedition during thewinter of 1902–1903 was the most important. After 1906, Birkeland extendedhis terrellaexperiments and applied the electromagnetictheory to includesolar and cosmicphenomena. Hissimula- tions of the influence of corpuscular radiation from the Sun on Saturn’s rings, and comet tails are fascinating, especially coming atatime when other scientists maintained that the Earth was surroundedbyvacuum. His concepts of stars as sources of matter for interstellar space and the importance of electromagnetic forces throughout the cosmos are markedly less known. His theoretical 4 INTRODUCTION

Figure 1. King Oscar II appointed Birkeland Professor of Physics in October 1898. The appointment was announcedinaformal, four-page document. In accepting this appointment Birkeland promised to support royal authority. proposals were rooted in laboratory experiments designed to simulate space interactions. Birkeland blended a unique intuition with talent for technical work. His approach generated fruitful frameworks for understanding basic plasma processes. Birkeland published eighty-eight scientific papers; thirty-two of them ap- peared in Comptes Rendus des Sciences, the journal of the French Academy. The others were published in German, Scandinavian, and English journals. He also wrote three scientific books. His main treatise The Norwegian Aurora Polaris Expedition of 1902–1903 fills more than 800 pages in large format. The other two books are about 200 pages in length. Research activities in many different fields were new to Norway.Asmany as eight research assistants worked in his laboratory. Several scientists have ranked him among the world’s leading experimental physicists. (cf. e.g. Perratt, 1996). From 1901 to 1906 Birkeland turned to applied physics and technological development. Hisprimary motive for engaging inthis activity was to generate the funds needed to support ambitious research projects and to build amodern researchlaboratory whose cost greatly exceeded what theUniversity could afford.All together Birkelanddeveloped sixty patents in ten different subject INTRODUCTION 5 areas. In one field, the production of agricultural fertilizers, he earned large sums of money. Birkeland invented the plasma arc leading to the Birkeland-Eyde method for industrial nitrogen fixation and the founding of Norsk Hydro that today remains one of Norway’slargest industrial enterprises. While Norwegians mostly remember him for his leading role establishing Norsk Hydro, Birkeland viewed the effort as a diversionary episode in his life. Birkeland’s first patent concerned an electromagnetic cannon that is similar in concept to a rail gun. He then formed his first company called Birkeland’s Firearms. A modern rail gun was used to simulate how the Space Shuttle Columbia’s left wing was breached by ahigh-speed packet of foam. Birkeland also held patents related to electrical switches and even formed a small company for their industrial production. He also took out patents related to hardening whale oil to produce magarine, electromagnetic devices to probe for metals and minerals, the refining of oil, and mechanical hearing aids. In 1906, Birkeland applied for funds from international financiers in Stockholm to support research for utilizing atomic energy; in 1915, he sought support to build automated meteorological stations to improve severe weather predictions. From 1908 to 1910 he conducted extensive radiowave experiments related to telegraph and telephone technology. To help improve radio communications capabilities, at his own expense, Birkeland erected a 15-meter high transmitter antenna on the roof of theUniversity’s main building andbuilt receiving stations a few miles away. Birkeland’s p ioneering researchin geophysics and applied physics engen- dered awidespread spiritof pride in hisnewly independent homeland.On February 1, 1913, the front page of the Aftenposten, Norway’s largest newspaper, featured a summary of a lecture Birkelandhad presented to the Norwegian Academy on the previous evening with King H˚akon˚ VII sitting in the front row. Hisability to attract and stimulate young scientists laid the foundations for Norway’s strong presence in present-day space research. Many of Birkeland’s insights about thephysics of space passed unrecognized until satellitesgaveustheability to survey electromagneticenvironments beyond our atmosphere. He introducedbasic concepts that are central to modern space physics. They includecalculations of energetic-particle motions in dipo- lar magnetic fields, his description of geomagneticsubstorms, andhis postulate that electric currents flow along magnetic field lines into and out of the upper atmosphere, today called the Birkeland currents.These currents link theupper atmosphere to the distant reaches of geospace. He also discovered theglobal pattern of theelectric currents inthe polar ionosphere. Based on hisownlab- oratory simulations, Birkelandfirst suggested that how charged particles from the Sun controlgeomagnetic disturbances and might influence suchinterplan- etary phenomena as Saturn’s rings, comet tails, and zodiacal light. As space 6 INTRODUCTION measurements accumulated in the 1970s, attitudes towards Birkeland’swork on electric currents in space changed to admiration and acceptance. In retrospect, we see that Birkeland’s geomagnetic and auroral research, conducted between 1894 and 1913, was decades ahead of its time. Birkeland was tireless, energetic, and enthusiastic, constantly involved in simultaneous projects. Thus, he often worked both days and nights. He in- troduced innumerable ideas but never spared himself. He possessed a lively imagination and a sense of humor that tended toward self-deprecation. Some faculty colleagues were envious of Birkeland’s ability to attract generous government support for his research. He identified and employed many promising young students who grew to become important leaders in the Norwegian scientific community. Among these were Sem Sæland, Carl Størmer, Lars Vegard, Ole A. Krogness, Thorald Skolem, Karl and Olaf Devik. They all contributed to the development of cosmic geophysics, a new field of research started by Birkeland. He disliked the University’s formal criteria for appointing new professors, and often voted with the minority. Feeling that the University had too many German-speaking professors, Birkeland actively supported the candidacy of chemist Ellen Gleditsch, a former assistant to Madam Curie, to become the first female member of the faculty. Olaf Devik (1971)described Birkeland’s lectures: “When he lectured on a subject whichhe was especially fond of, he broughtabreath offresh air into theclassroom. He would operate electrical equipment far beyond their rated capacities and burn out 100 Ampere fuses with dignified nonchalance” (Devik, 1971).Heseldom hesitated to disagree with explanations inphysics textbooks. As his research responsibilities grew, Birkelandfoundless andless time to prepare and give lectures, and often paid his assistants to teachintroductory courses. The concept of maintaining goodhealth with regular exercise and a good diet was alien to Birkeland’s m ind.Healways workedhard,andhis assistants often had to remindhimtoeatlunch. From his daysasastudent, he experienced frequent bouts ofinsomnia. Some ofhis earlyradiowave experiments led to serious hearing defects. In his later years, Birkeland grew even more absent- minded anddisorganizedin his daily life. He jotted small notes about schedules, budgets, and scientific ideas on singlesheets of paper, then leftthem in random places. A rapid deterioration in his health was a criticalfactor inBirkeland’s decision to emigrate to Egypt in 1913. The last two years ofhis lifewere particularly difficult. He slept poorlyandbecame inordinately suspicious of strangers. Birkeland’s lifealso spanned a period of political change, from whose influence not even theoretical physicists are exempt. Incorporatedinto theSwedish Kingdom in 1814 after the Napoleonic wars, Norwegians found themselves INTRODUCTION 7 mired in a political and economic backwater. Between 1840 and 1900, more than 600,000 Norwegians emigrated to the United States. Others stayed and struggled for an independent Norway. Birkeland always viewed his scientific and applied work through the prism of Norway’s contribution to civilization. Althoughhewasvery much a Norwegian nationalist, he was also a European cosmopolitan. In the summer of 1914, the century-long peace established at the Congress of Vienna collapsed while Birkeland was in Egypt conducting research on a solar effect called zodiacal light. His two young assistants were recalled to Norway for military service. In early 1917, alone and in poor health Birkeland decided to return to Norway. The war dictated that he travel to Kristiania via Japan and the Trans- Siberian railroad from Vladivostok. His companion, Dr. Eriksen, the Danish Consul to Egypt, was on his way back to Copenhagen. However, when they reached Tokyo in early May, Eriksen changed his plans and returned to Egypt. Birkeland died in Tokyo about a month later, an indirect casualty of the con- flagration we now call World War I. In the course of our research for this book, we uncovered documents from May and June 1917 that cast new light on Birkeland’s last days in Japan. At the University commemoration of Birkeland’s death in 1917, Vice- Chancellor Sæland characterized Birkeland as “a scientificexplorer bythe grace of God.” In theeyesof all Norwegians hewasbothfamous and wealthy. Atthetime ofhis death,aninternational committee was inthe process of nominating him for theNobel Prize inPhysics. Altogether he was nominated foraNobel Prize four times eachinchemistry and physics. The government of Norway honored Kristian Birkeland as theworld’s first space physicist. His portrait, along withhis terrella experiment and some originaldrawings, appears on the 200 kroner banknote, first issuedin 1994. In addition, a large international Birkeland Symposium was held in 1967, and the annual series of Birkeland lectures was established at the Norwegian Academy for Science and Letters. Birkeland was the complete scientist,agifted theorist, as well as an imag- inative laboratory andfield experimentalist. He devisedlaboratory experiments that, for theirtime, were of unprecedented size and complexity, and hemadethem work. Many studies have been madeof eminent scientists. Some scholars are purposeful, follow straight lines toward their goals, and never allow interruptions or distractions. Others takeadifferent approach. Likegardeners who develop hybrid roses, they try many different methodsand techniques with varying degrees of success. Birkelandbelongs to this latter category. To begintounderstand Birkeland’s accomplishments and thearguments against them, we must set asidethe technological world we take for granted and imagine ourselves at the end of the 19th century. We must continually ask, 8 INTRODUCTION

“What did scientists of the time know?” For example, although Birkeland began working with “cathode rays” in 1894, it was not until 1897 that Joseph John Thomson (1856–1940) identified them as the electrical corpuscles we now call electrons. With this knowledge, Thomson developed a model in which positive and negative charge was distributed more or less uniformly throughout the atomic volume. However, Thomson’s model wrongly predicts atomic emission spectra. It was not until 1910 that Ernest Rutherford (1871–1937) experimen- tally demonstrated that atoms consist of electrons orbiting very small nuclei of positive charge. According to Maxwell’s equations, electrons in Rutherford’s planetary atom should radiate energy as light and collapse into the nucleus. In 1913, Niels Bohr (1885–1962) took the first step toward understanding the quantum universe we take for granted today. There is also a problem of language. The 19th and early 20th centuries were times of singular growth in scientific understanding. Reading early papers chal- lenges scientists accustomed to textbooks written after World War II. Standard terminology, mathematical notation, and physical units have now evolved that allow readers access to the thoughts of American, European, or Asian scientists without requiring mental gymnastics to map between them. However, reaching this stage of synthesis required the unification of partially described phenomena anddiverse metaphors into a common nomenclature. Likeanyexplorer, Birkelandhad to invent new language as his research uncovered new layers of physics. As the first to examine disturbance records from around theglobe during magnetic storms, Birkeland estimated that currents of several millions Amperes must flow inthe upper atmosphere. He understoodintuitivelythat onlytheSun could drive and sustain suchlarge electrical currents. Consequently, currents inthe upper atmosphere must connect to generators in deep space via mag- netically field-aligned currents. Indeed,Birkelandfound the predicted currents replicatedin laboratory simulations. He reached truly innovative conclusions about thephysics of the aurora anddisturbances inthe Earth’s magnetic field. Others shared neither Birkeland’s intuition nor his trust in laboratory simulations andfeltthey could explain magnetic perturbations observed on the ground as the results of a system of equivalent currents flowing inthe upper atmosphere. Decades passedbefore Naoshi Fukushima showedin 1969 that it is impossibletodistinguishbetween Birkeland’s a n d the equivalent-current systems based on ground magnetic recordsalone. Field-aligned currents can only be detected with magnetometers on spacecraft flying above ionospheric current layers. Scientists are human beingswhomayfeel triballoyalties that blind them to truthsexpressedinunfamiliar words. In 1892, William Thomson (1824–1907), better known as Lord Kelvin, expressedhisopinion that no matter passes between the Sun and the Earth. In spite of mounting evidence to INTRODUCTION 9 the contrary, Kelvin’s opinion was definitively rejected only after satellites had passed though the boundary of the Earth’s magnetic field into the solar wind. Writing a scientific biography of Kristian Birkeland about a century removed from the time of his greatest achievements presents two further difficulties. First, Birkeland was an extraordinary theoretical, experimental, and applied physicist whose interests were both broad and urgent. Coming from a middle class family, he lacked the independent resources needed to support his scientific investigations. An international scholarship and his inexpensive but ingenious experiments at the University of Kristiania established his scientific reputation at a time when Norway sorely needed heroes. This renown provided entrée´ and credibility when he approached the Storting, Norway’s parliament, in search of funds to support challenging field experiments. It also attracted the attention of industrialists who approached the Norwegian Wunderkind for advice in solving practical problems. In the first decades of the new century, Birkeland analyzed and published the results of his laboratory experiments while developing new practical concepts and demonstrations to support sixty patents. More and more Birkeland invested money earned from industrial inventions to support his scientific research. Because he was involved in so many projects at once, a simple chronological listing of events would lead to confusion. For this reason, we chose to pursue a thematic development. A second difficulty arises from the fact that Birkeland never kept a diary. Most of our knowledge ofhimasaschoolboy,asauniversity student, in his private lifeand marriage as well as his conflicts with Sam Eydeand Carl Størmer is largely based on thewritings and recollections ofhisclose assistants, Sem Sæland,Ole A. Krogness, and theDevik brothers, Olaf and Karl.They regarded Birkeland as a genius. One of the authors (A.E.) conducted extensive interviews with Olaf Devik and was given full access to his archives. In The Norwegian Aurora Polaris Expedition of 1902–1903,wwhich we refer to as NAPE, Birkeland does discuss the development of his thoughts concerning laboratory andfield experiments. He also provides candid descriptions of and his reactions to physicalhardships anddangers experiencedduring the auroral expeditions. In addition, heplanned to write Volume III, mainly concentrating on auroral physics and the results of experiments withhis 70-cm diameter terrella. Unfortunately, Birkelanddiedbefore thisvolume was written. Shortly after his deathinTokyo, colleagues assembled all of Birkeland’s s c ientific papers for return to Norway. Theship bearing the papers was lost at sea, and withit access to Birkeland’s mature thoughts on auroral phenomena. Atthe present time, Birkeland’s name and contributions are not well known outside Scandinavia. External recognition is mostly confined to scientists who study the Earth’s space environment. Even among them, appreciation of Birkeland’s work is fragmentary, mainly concerned with the field-aligned 10 INTRODUCTION currents that electrically couple the ionosphere to deep space. His laboratory simulations of the solar system and his technological innovations remain largely unknown. Lucy Jago’s book The Northern Lights (2001) is the most compre- hensive biography of Kristian Birkeland available in English. The book is well written in a journalistic style that necessitated telescoping events and, in the absence of documentation, making “reasonable” assumptions about what ac- tually occurred. It strongly emphasizes Birkeland’s personality and the reactions of others to him. We share much common ground. However, as auroral scientists, we emphasize Birkeland’s documented scientific and technological accomplishments and his place within the development of space physics over the past century. This book is divided into five major sections, each with two or three chapters. The first sets the stage with brief summaries of the political and scientific status of Norway at the end of the 19th century. It also describes the Birkeland family and Kristian’seducation through postgraduate studies. The second section deals sequentially with Birkeland’s geomagnetic and solar system research. His geomagnetic studies were conducted during field expeditions and in laboratory simulations with the terrella serving as an anode to attract energetic electrons from the “Sun”. In his solar system simulations, Birkeland reversed the electric polarity of the terrellatosimulate theoriginof sunspots and comet tails. From these experiments, he came to a profound realization that theuniverse must be filled withionized gas that we now call plasma. Thethird section dealswith Birkeland’s technologicalinventions related to high-current switches, electromagnetic cannons, and nitrogen-fixatedfertilizers. The fourth andfifth sections, respectively, describeBirkeland the man as perceived through available documents andinterviews with Olaf Devik,andhis heritage in Norwegian education and space physics. In addition to the standard references at theend of the book, interested readers can also find copies of several previously unavailable documents as well as lists of Birkeland’s publications andpatents. Part I: Background and Education

CHAPTER 1

AT THE 19TH CENTURY ’S END

1.1 UNION OFNORWAY AND SWEDEN

In the aftermath of the Napoleonic wars, England and Russia agreed that Norway should become a part of the Swedish kingdom. From the outset the Union was unstable. In 1814, the year of the forced union, Norwegians ratified their own constitution. They experienced two bothersome limitations to their autonomy. First, Norway was not free to appoint its own foreign ambassadors. Second, their Swedish King held veto power over enactments of the Norwegian Storting(Norway’s parliament). Relations between Sweden and Norway dete- riorated severely in the first half of 1905, leading to the Union’sdissolution. On June 1, 1905, King Oscar II of Sweden vetoed a Norwegian resolution to form its own Consular Service. The Storting declared that the King’s action was unconstitutional. Existing law allowed the king to exercise a veto only with the concurrence of his cabinet. Norway unilaterally ruptured the Union on July 7, 1905, and waited anxiously to see if Sweden would declare war. In the months before the final break, the Storting prudently consulted with critical countries to assure international acceptance for their independence initiative. The world-famous Norwegian explorer and oceanographer Fridtjof Nansen (1861– 1930) helped carry the day by persuading the British government to support separation. A September plebiscite, inwhich only men could vote, certified the degree of popular support for dissolving theUnion. Almost unanimously Norwegians voted to end theUnion, 368,208 for and 184 against. A second referendum, held inNovember, decided whether newly independent Norway would become a republic or remain a constitutional monarchy. Newspaper editors and other prominent citizens encouraged votes for a monarchy, hoping thataSwedish prince would bechosen as the king and thus maintain good relations with the strong neighbor. When theSwedish prince declined, Norway turned to the Danish prince Carl who accepted and assumed the Norse royal name H˚akon˚ VII. 12 CHAPTER 1

Figure 2. TheRoyal Frederik University of Kristianiaand University Square as theylooked when Birkeland was a student. Birkeland’s ofﬁce and laboratory were in the Domus Media, behind the column fa¸cade.¸

1.2 THE ROYAL FREDERIK UNIVERSITY IN KRISTIANIA

In 1811, King Frederik VI of Denmark established Det Kongelige Frederiks Universitet (The Royal Frederik University) in Norway’s capital, Kristiania. It was renamed University of Oslo in 1939. Following Birkeland’s example in his main book, The Norwegian Aurora Polaris Expedition of 1902–1903, we simply refer to it as the University of Kristiania. In the beginning, the University was scattered throughout the city. The Astronomical Observatory(1832) was the first building specifically built for the University. In 1851, the University moved into the new Domus Media around which the main campus formed. This was centrally located on the city’s main street, Karl Johan Gate 47 (Gate is the Norwegian word for street). At the beginning of the 20th century,it was still the largest building along the street. Figure 2 shows its impressive facade¸ of columns and shallow steps. The Royal Castle and the Storting were its nearest neighbors to the north and south, respectively. The physics group moved into Domus Media in 1851. Not long afterwards, two other monumental buildings were completed on the new campus. The main university library, Domus Academica, with several lecture halls lies to the west of Domus Media, and to the east is the first festival building later known as the Old Banquet Hall. The Philosophy Faculty then had two major sections. The first concerned the disciplines of philosophyandhistory, the second mathematics and science. By 1860, an institute of physics was recognized withits own faculty. In 1891, the institute became the Department of Physics. AT THE 19TH CENTURY’S END 13

Figure 3. Christofer Hansteen (1774–1873),the first professor at theUniversity of Kristiania to studygeomagnetism and auroral lights. A fascinating researcher, Hansteen had a profound influence on the University’s early development. Christofer Hansteen (1784–1873), shown in Figure 3, was a character central to the University of Kristiania’s development. A Norwegian by birth, Hansteen received his scientific education at the University of Copenhagen under the direction of Professor Hans Christian Ørsted (1777–1851). We return to Ørsted and Hansteen in our discussion of geomagnetism. In 1816, Hansteen returned to Norway to become the University’sfirst Professor of Astronomy and Applied Mathematics. He was the driving force responsible for building the Astronom- ical Observatory on land that would become a part of the University campus. By 1885, when Birkeland entered the University,the total number of students andfaculty was nearly 600. There was a single Professor of Physics, Oscar Emil Schiøtz (1846–1924).However,Birkeland worked more closelywith Carl Anton Bjerknes (1825–1903), Professor of Applied Mathematics andfather of his friend VilhelmBjerknes (1862–1951).The younger Bjerknes later gained internationalfame for hiswork on the meteorology of weather fronts. Two other professors who greatly influenced Birkeland were Hans Geelmuyden (1844– 1920), head of the Astronomical Observatory, and Henrik Mohn (1835–1916), director of thenewly established Meteorological Institute.

1.3 EARLY INVESTIGATION OF THE AURORAAND GEOMAGNETISM

The beauty and mystery of shimmering aurorallights inthepolar sky have long fascinatedhumanity (cf. e.g. Brekkeand Egeland, 1994).These glorious 14 CHAPTER 1 lights have many names. In his treatise on Meteorology, Aristotle (384–322 B.C.E) referred to them as χασ µατα (chasms or cracks in the sky) shining with blood-red light. For the Vikings, they were simply “northern lights”. Early modern scientists such as Galileo (1564–1642) and Pierre Gassendi (1592– 1656) used the Latin aurora borealis or“northern dawn” to describe their red appearance at the latitudes of southern Europe. In 1770, during the voyageof Endeavor, Captain James Cook (1728–1779) was the first European to observe auroral lights in the southern hemisphere (aurora australis). Birkeland used the term aurora polaris to indicate that auroral phenomena occur at magnetic high latitudes in both hemispheres. For many centuries, the magnetic properties of lodestones and magnetite were known and used as navigational aids. William Gilbert (1544–1603) conducted the first systematic investigation of the Earth’s magnetic field and published the results in DeMagnete (1600). His most important conclusion was that “the Earth itself is a largemagnet” with its greatest strength at the poles. Gilbert also noted that the magnetic poles are displaced by afewdegrees from the geographic poles. Scientists [Gilbert (1600); Gauss (1839, 1841); Chapman and Bartels (1940)] long recognized that the Earth’s magnetic field changes continually and often violently. When Galileo first turnedhistelescope on the Sun in 1610, he discovered that it lacked the perfectly smooth surface postulatedbyAristotelian cosmology. Rather it was pockedby blemishes now called sunspots. Thereafter, the behavior of sunspot activity was carefully monitored. However, it was not until the 1840s that Heinrich Schwabe (1789–1875) showed that the number of sunspots varies considerably over an 11-year cycle. In 1716, Edmund Halley (1656–1742)found aclose association between geomagnetic disturbances and visible auroraldisplays. During the year 1741, Anders Celsius (1701–1744) and Olaf Peter Hiorter (1696–1750) conducted investigations inwhich they noticed that theorientation of a suspended magnetic needletilted either to the leftorrightof the geomagneticpole direction whenever auroral lights were visible. Clearly, auroral perturbations of compass directions posed serious threats to navigation. However, Celsius could not explainwhy an auroraldisplay affected compass directions. More than a century later, Birkeland proposed the first scientifically correct explanation of this mysterious relationship. He argued that fluctuations of the geomagnetic field providecriticalinformation about theelectrical currents flowing inthe Earth’s space environment and about activity on the Sun. Whilethe Earth’satmosphere protects us from hazardous radiation, most information carriedbymagnetic field variations reaches the ground. During the early years of the 19th century,whileChristofer Hansteen was studying at the University of Copenhagen, the Danish physicist Hans Christian AT THE 19TH CENTURY’S END 15

Ørsted (1777–1851) was examining changes in the orientations of magnetic needles whenever electric currents flowed in nearby wires. In 1820, Ørsted published his discovery that electric currents cause magnetic disturbances. Later, Michael Faraday(1791–1867) demonstrated that time-varying magnetic fields induce electric currents. James Clerk Maxwell (1831–1879) unified the work of Ørsted and Faraday, expressed in four fundamental laws of electromagnetism. As Ørsted’s student, Hansteen was aware that Halley detected similar deflec- tions of compass needles during auroral displays. In 1812, Hansteen entered a European competition to answer the question: “Can we explain the Earth’s magnetic phenomena with a single magnetic axis, or must several axes be assumed?” Hansteen’s (1819) thesis Untersuchunguber ¨ den Magnetismus der Erde won the competition. He concluded that two axes, or four magnetic poles were needed to explain existing measurements of the Earth’s magnetic declina- tion. The concept of a quadrapole magnetic field was not new. Hansteen cited it as part of Halley’s geomagnetic model, and he spent a good deal of time trying to determine where to place the four poles on a globe. Hansteen built several new instruments for measuring the total field and the magnetic declina- tion to support his geomagnetism studies. Between 1828 and 1830, he traveled across Siberia to China to look for the second pole on the northern hemisphere. Althoughheneverfound a fourth magneticpole, theglobal magnetic map he derivedduring this expedition was of considerable use to Carl Friedrich Gauss (1777–1855). Although the auroral problem was not of centralinterest to Hansteen, in 1825, he surmised:“The northern lights must be part of ashining ring, with a diameter of about 4,000 kilometers, of which each observer sees hisown segment. This leads us to suppose that there must be some connection between the aurora and the Earth’s magnetism.” (cf. e.g. Trromholt, 1885). Muchlater inthe 19th century, Herman Fritz (1830–1893)in 1881 clearly documented that the aurorallights most often occur about 23◦ from the magnetic poles. Systematic recordings of simultaneous geomagnetic field variations began in 1834, when Carl Friedrich Gauss first deployed magnetometers of the Gøttingen Magnetic Union at stations around Europe. Gauss’ publication Algemeine The- orie des Erdmagnetismus (1839) initiated the modern study of geomagnetism by applying the gravitation potential theory of Pierre-Simon Laplace (1749– 1827) to the Earth’s magnetic field. Gauss argued that magnetic fields detected on the ground have sources inside Bint and outside Bext the Earth.Hethen demonstrated a mathematical technique to separate them. He concluded that Bint was due to a large, permanent field from insidethe Earth that varies from ap- proximately 30,000 to 60,000 nanotesla (nT)between the geomagnetic equator and thepoles. The magnetic-field axistilts about 11◦ to the Earth’s rotational axis. To a good approximation, the geomagnetic field is representedbyasimple