Solar cycle and long term changes in the solar wind

Abstract

During the last four years substantial progress has been made in the study of variations of the solar wind on time scales of decades to hundreds of years. Solar cycle changes in 3 dimensions have been described and the cyclic evolution of solar sources studied. Work on longer term changes has made a good start. Data sets and methods of scientific analysis are being developed. Estimates have been made of pre-space-age solar wind properties. The existance of the eleven year cycle for the last 1,500 years was studied. The non-random nature of variations over many solar cycles was confirmed but there is still controversy concerning the periodic nature of the 80–100 year variation. There is evidence that variations of the Maunder and Sporer types may be periodic.