The next missions scheduled for detailed studies of the Sun and solar atmosphere are Parker Solar Probe
and Solar Orbiter
Parker Solar Probe, launched August 12, 2018, moves in a highly-elliptical orbit, using gravity-assists from Venus to move the orbit perihelion closer to the Sun with each pass. The goal is to get the spacecraft to fly through the corona at a distance of 9.5 solar radii. Primary science operations are conducted when the spacecraft is within 0.25 astronomical units (AUs) from the Sun, so that portion of the orbit is colored red. The nominal end of mission for Parker Solar Probe is 2025, so the orbit fades away after that year.
Solar Orbiter uses a series of Earth and Venus gravity assists to move its orbit perihelion (the closest distance from the Sun) to a distance inside the orbit of Mercury for detailed solar monitoring. The primary science operations for Solar Orbiter are conducted when the spacecraft is within 0.5 AUs from the Sun.
The visualizations below were generated before the launch of Parker Solar Probe, assuming a launch date of July 31. 2018. They are included here for reference.