The remaining parts of those atoms are left with a positive charge, and the detached negative electrons are free to move about. When enough atoms are ionized to significantly affect the electrical characteristics of the gas, that is when we call the atoms plasma. In many cases interactions between the charged particles and the neutral particles are important in determining the behavior and usefulness of the plasma. The type of atoms in a plasma, the ratio of ionized to neutral particles and the particle energies all result in a broad spectrum of plasma types, characteristics and behaviors. These unique behaviors cause plasmas to be useful in a large and growing number of important applications in our lives.
Plasma physics utilizes classical mechanics, electromagnetic theory and statistical physics.
This interaction differentiates the behavior of plasmas from that of the more familiar gases. Plasmas are of great physical interest for a number of reasons. Deep in the core of stars hydrogen is fused into helium releasing huge amounts of energy. One long-term goal of plasma for researchers is to replicate this process in the laboratory. Inertial confinement schemes attempt to initiate fusion burns by imploding fuel pellets using high power lasers or particle beams.