Complex sentence: The Sun's hot corona continuously expands outward into space, creating the solar wind, a stream of charged particles, the spatial extent of which defines the heliosphere and with an outer boundary that is the heliopause at roughly 100 astronomical units.
Split into simpler sentences: The Sun's hot corona continuously expands outward into space, creating the solar wind, a stream of charged particles. The spatial extent of the influence of the solar wind defines the heliosphere, and its outer boundary is the heliopause at roughly 100 astronomical units.