POLAR Investigation of the Sun - POLARIS
  The POLAR Investigation of the Sun (POLARIS) mission uses a combination of a gravity assist and solar sail propulsion to place a spacecraft in a 0.48 AU circular orbit around the Sun with an inclination of 75 degrees with respect to solar equator. This challenging orbit is made possible by the challenging development of solar sail propulsion. This first extended view of the high-latitude regions of the Sun will enable crucial observations not possible from the ecliptic viewpoint or from Solar Orbiter. While Solar Orbiter would give the first glimpse of the high latitude magnetic field and flows to probe the solar dynamo, it does not have sufficient viewing of the polar regions to achieve POLARIS' primary objective : determining the relation between the magnetism and dynamics of the Sun's polar regions and the solar cycle. 
T. Appourchaux, P. Liewer, M. Watt, D. Alexander, V. Andretta, F.   Auchere, P. D'Arrigo, J. Ayon, T. Corbard, S. Fineschi, ...