This is a 3-dimensional emitter and the particles are radially emitted from the outside of the cylinder. In the viewport, the cylinder is represented by two circles, which define its length. Radius and height can be controlled via the emitter’s "Scale" settings. You can position (W key), rotate (E), and scale (R) this emitter.
Speed
Here the particles' initial speed is defined in metres per second. Higher values will generate more particles per frame. Faster particles act with stronger forces on other particles or objects. The number of emitted particles also depends on your → “Resolution” settings. A value of 0.0 disables the emission of particles. Please note that it is not possible to fill the emitter or create volumes. If you want to create a filled object use a "Cylinder" node and a → "Fill Object" emitter. A value of 0.0 → stops the emission of particles.
V random
To avoid regular emission, it is possible to randomly displace the particles with these functions. The value should range between 0 and 1, but can be higher, as well. “V” stands for vertical.
H random
To avoid regular emission, it is possible to randomly displace the particles with these functions. The value should range between 0 and 1, but can be higher, as well. “H” stands for horizontal.