Report on the 6th International Symposium on Ball Lightning (ISBL99) held on August 23-26, 1999, in Antwerp, Belgium, by Geert Dijkhuis

Very nearly two years after the mountain-side meeting in Tsugawa-Town, international ball lightning scientists met again in the bustling port city of Antwerp, Belgium. As home town of Flemish baroque painter Peter Paul Rubens in its 16th-century heyday, Antwerp now shines world-wide as diamond polishing and trade center. Participants found comfortable and convenient lodgings on down-town De Keyserlei in the Florida Hotel facing the monumental railway station and the diamond district. A short bus drive shuttled participants to and fro university grounds in suburban Antwerp. The organiser gratefully acknowledges hospitality at Antwerp University, and support by main sponsor Dow Benelux N.V. and six Dutch companies.

Following the Japanese lead in Tsugawa, hand-outs at registration included full-fledged Symposium Proceedings recording 49 papers on 289 pages by authors from 12 countries. Their abstracts had been posted beforehand on the Internet on the new ICBL home page http://home.wxs.nl/~icblsec.

The Participants List identified 28 ball lightning investigators, or 5 each from Japan, Russia, and the USA, 3 each from the UK and the Netherlands, 2 from Belgium, and 1 each from Austria, Finland, Germany, Italy and Spain. A representative from Plenum Press in London attended the symposium with a table top display promoting a new monograph on ball lightning. In the Opening Session on Monday morning in Aula of Antwerp University G.C. Dijkhuis welcomed all participants, and ICBL President Stanley Singer in particular. His Opening Address reviewed a puzzling record of laboratory analogues of ball lightning that proved irreproducible, from Van Marum's 18th-century Leyden jar discharges down to present-day laser and combustion tests. From Moscow, G.E. Norman followed up with a Keynote Address in impeccable english relating how ball lightning research in past decades rose from ridicule voiced during his first lecture, to its current status as a challenge to science. In this vein M. Stenhoff announced his forthcoming monograph on ball lightning, illustrating its unsolved problems with scorched dress tissue in a frame. And during intermission S.A. Blommaert added a proper hands-on touch with a fiery table-top demonstration of high-voltage discharge in air from a Tesla coil resonator, highlighting his feat of wireless power transmission to a light bulb through radio waves.

After lunch in the nearby Medical Center restaurant, topical sessions started in the Lecture Room of the Physics Building with Data collection and analysis, chaired by R.C. Jennison. The first talk presented further statistical analysis of eyewitness reports by the Japanese Information Center on Ball Lightning, aligning its sample data with other countries, except for a strong preference to appear in fair weather. But fair- and foul-weather subsamples in the Russian data bank of her late husband show only minor differences according to I.G. Stakhanova's contribution, as presented by G.E Norman. V.L. Bytchkov followed up with regression analysis of Russian and Austrian data giving power-law correlations of diameter and lifetime favouring fractal models of ball lightning over hydrodynamic or plasma theories. Meanwhile, P. Toselli's initiative for an Italian Ball Lightning Archive combining recent events with Galli's early 1900's collection was detailed on data sheets posted in the lecture room by R. Fedele.

The afternoon coffee break shifted the topic to Theory and models, chaired by D.K. Callebaut. The first talk by G. Endean soberly assessed damage to ball lightning research by extravagant theorizing, and urged adherence to the virial theorem which falsifies many such models. From rocket-triggered lightning in Japan, H. Kikuchi proposed artificial ball lightning reproduction in cusped electric fields at coils in trailing copper wires launched into a thundercloud. Citing recent observations M. Stenhoff proposed 'superbolts' as natural source of intense radio pulses at frequencies and power levels that might revive Kapitsa's microwave resonance model in free air and inside aircraft. Around 6 p.m. the first symposium day ended with K.W. Wevers's digitized slide show reviewing Convectron's track record on its bosonic ball lightning model and test program in the Netherlands. Outside the lecture room, sun-bathed scenery invited us to a pleasant summer evening amid the trappings of city life. Next morning at 8:45 h the theory session reopened with V.L. Bytchkov in the chair. For the Japanese microwave test facility M. Kamogawa calculated that ceramic plates placed in quasi-periodic Fibonacci or scaling Cantor bar sequences, localize and magnify field intensities up to 300 times by multiple interference. And fireballs in the test section show unexpected motion away from anti-nodes and towards nodes in the electric field, suggesting thermal effects on the plasma conductivity near the cavity walls. Focussing on the high-energy aspect of ball lightning A.I. Nikitin calculated huge energy storage capacity by charge separation of electrons and ions in coaxial circulation confined by a spherical shell of charged and polarized water molecules.

After coffee break H. Kikuchi chaired the second theory session. A.I. Nikitin opened by connecting his dynamic capacitor model with a parent lightning, and with capacitor discharge through supersonic and moisted jets from a Laval nozzle. In A.F. Ranada's magnetic knot scenario, ball lightning appears when magnetic helicity retards decay of tangled plasma streamers towards a force-free state. And T.J. Tuomi materially clarified Ranada's linked streamer topology through 3D pictures of beads on tortuous string loops obtained from analytic solutions for current and field lines.

After another sun-lit lunch break, quantum theory and relativity entered in the session chaired by A.F. Ranada. Solid-state models of alkali metals lead E.A. Manykin and G.E. Norman to a Rydberg matter condensate of excited nitrogen atoms as non-ideal plasma state in air at room temperature, with Madelung energy as in ionic crystals. From a quantum-like approach to non-linear wave propagation R. Fedele expects 3-D self-trapping of charged bunches analogous to solitary waves. For ultra-high internal energies A.N. Vlasov envisions ball lightning as a relativistic ring vortex with Bose-Einstein condensation of coherent electrons catalyzing possible fusion reactions.

After coffee break G.E. Norman chaired the day's closing session. Thermodynamics of a stretching string-based vortex lattice led G.C. Dijkhuis to state equations modelling accidental plasmoid formation from coiled copper wire as self-confinement and reverse evolution seen in bunches of charged vortex rings in superfluid helium. And diligent time keeping by successive chairs allowed an open floor for D. Fryberger's post-deadline contribution connecting his vorton concept for elementary particles with ball lightning.

Next morning the third symposium day opened with the last theory session, chaired by A.I. Nikitin. Proceeding from Helmholz's equation, G.H. Arnhoff derived a spherical and sourceless vector field which subsists without end in vacuum as a radiation bubble. G.C. Dijkhuis followed up by reading P.H. Handel's treatment of ball lightning as an air-borne plasma caviton receiving feedback from atmospheric maser action induced by lightning. After coffee break the topic moved on to Experiments and tools, with T.J. Tuomi chairing the first session. Repeating J.D. Barry's combustion experiments in propane-air mixtures, I. Wieder could not reproduce the long-lived fireballs, but instead he obtained cool reddish balls keeping their shape while they last. Using ceramic plates with fractal spacing of Cantor bars, H. Ofuruton reported evidence for plasma fire from Anderson localization of microwave power in the Japanese test facility.

After lunch the experimental session resumed, now with H. Ofuruton in the chair. It opened with A.I. Klimov's talk presenting detailed test parameters and plasma diagnostics for diffuse or filamentary plasmoids produced with a Tesla generator or microwave power, and for cluster plasmoids created by erosive high-voltage pulses in supersonic gas flow. P.M. Koloc followed up with two consecutive talks. His photo and video images show ball lightning in the laboratory as a spheromak magnetic field structure dressed in a hyper-conducting mantle of runaway electrons. At energy inputs up to 5 kJ in atmospheric air, their lifetimes attained many tens of milliseconds, both in clean and in dusty plasma conditions.

After a last coffee break V.L. Bytchkov chaired the closing session for experiments. In two consecutive talks on micro ball lightning generation and transport during underwater spark discharges T. Matsumoto showed scanning electron micrographs and X ray spectrographs of electrode material with transmuted elements. In his view micro tornadoes of interconnected electrons left traces from nuclear collapse of electrode material and ions in the electrolytic solution. And in remaining minutes the session chairman exhorted us to use correlations of observables now emerging from the data banks as benchmark test both for theories and laboratory reproduction efforts.

With 'thank you and goodbye' conveyed to all participants and to our friendly hosts, this organizer was happy to announce Peter Handel at the University of Missouri in St. Louis, MO, as organizer of the next symposium in the USA in 2001.

The Wednesday evening brought some forty participants and partners together for drinks and banquet in the Windsor Tavern on a tourist-packed De Keyserlei near the Florida Hotel. With sweltering heat of the summer's day gradually tempering, Trio Animato from Terneuzen added a Viennese touch with lovely chamber music composed by Mozart and Schubert. This convivial banquet upholds a lofty tradition in our discipline, bringing to mind the words of de Saint Exupéry, that the greatness of a profession is to unite people.

In the cultural excursion on Thursday morning our host and co-chair Dirk Callebaut guided remaining participants and spouses on a city walk through ancient Antwerp. The Museum Rubenshuis marveled us, preserving the great painter's spacious living quarters and workshop, still adorned by his remarkable private art collection. Our last coffee break looked out on 16-century City Hall guarded by the mythical giant whose "hand-throw" became "Ant-werp". We passed in awe through the splendor of its majestic cathedral. But where could we end this symposium better than in a lunch cellar tempting us with "Forbidden Fruit" to find out why Belgium leads the world in per capita beer consumption? Cheers!

Terneuzen,
Geert C. Dijkhuis
20 September 2000
ISBL99 organizer
ICBL Secretary
International Committee on Ball Lightning