The Local Void just happens to have its few regions separated by plasma filaments. It also has a lower number of galaxies in it that would be averagely expected.
The Local Void is surrounded by matter in the universe apart from one section which seems to have no great amount of matter.
The Local Sheet, which is our area of observable galaxies in the Milky Way, seems to be linked or effected by the Local Void. According to astronomy the Local Sheet is accelerating away quickly from the Local Void and is perhaps part of the Local Void wall.
Voids and plasma filaments
“Recent surveys of the more distant universe have revealed that galaxies lie in sheets and filaments with large regions of empty space called voids in between,” said McCall. “The geometry is like that of a sponge. What the new map reveals is that structure akin to that seen on large scales extends down to the smallest.”
Council of Giants: Our Intergalactic Neighborhood
The EU Theory (Electric Universe Theory) suggests that plasma may power and be the controlling force in the universe.
The EU Theory also suggests that plasma phenomena is scalable, that what effects and can be created in the smallest size can happen with the largest size.