The Solar Activity Cycle

Prof. Andé Balogh is Distinguished Research Fellow and Emeritus Professor of Space Physics at Imperial College, London and the past Director of the International Space Science Institute of Bern, Switzerland. His main research interests are solar and heliospheric magnetic fields, solar activity phenomena and the nature of heliospheric turbulence. Prof. Balogh has been a Principal Investigator on the Ulysses and Cluster space missions and is author and co-author of over 500 scientific papers on solar physics, space research and planetary physics; as well as editor of ten books, including eight volumes in Springer's Space Sciences Series of ISSI. His recent research has covered the measurements of the Sun's magnetic flux and its dependence on the solar activity cycle.Dr. Hugh Hudson is a Senior Researcher in the Space Sciences Laboratory at the University of California, Berkeley and an Honorary Research Fellow in the School of Physics and Astronomy at the University of Glasgow. His main research interests are high energy solar physics: solar X-rays, solar flares and Coronal Mass Ejections, but he has carried out research and has published on all aspects of solar physics. He has been associated with several space-based solar observatories, in particular YOHKOH and RHESSI. His most recent research topics have included the investigation of the phenomena associated with the recent unusual solar activity cycle and the observation and interpretation of highly energetic phenomena in the solar atmosphere.Prof. Kristóf Petrovay is Head of Department at the Department of Astronomy at Eötvös Loránd University, Budapest, Hungary. His main research interests are solar physics, astrophysical turbulence and magnetohydrodynamics. He has published widely on the topics of solar dynamo theory, magneto-convection in the Sun, the theory of sunspots, turbulence and turbulent diffusion in the Sun and in a broad range of astrophysical plasmas, as well as the origin and evolution of turbulent magnetic fields. In his recent publications, Prof. Petrovay has investigated models of the solar activity cycle and the physical processes that affect the operation of the solar dynamo.Prof. Rudolf von Steiger is Director of the International Space Science Institute of Bern, Switzerland and a Professor at the University of Bern. His main research interests are all aspects of the solar wind, with special reference to its composition and the physical processes that determine its variability and evolution, as well as its dependence on solar phenomena and solar activity. Prof. von Steiger has used solar wind composition data from the Ulysses, ACE and SOHO space missions and has over 160 publications in refereed journals, covering the observational and physical aspects of the composition of the solar wind. He has edited 19 books, including 15 in Springer's Space Sciences Series of ISSI. Recently, he has refined the complex analysis of solar wind ion composition measurements to further improve their accuracy and thus to improve their diagnostic capabilities.