A shield designed for the express purpose of deflecting particle and projectile based weaponry. The technology has been adapted for reliable use in personal defensive shields. These shields, unlike many others in science fiction, are not round projections of force, but form-fitting energy fields which permit penetration only by objects that move below a pre-set velocity.
As one would be unable to breathe within a shield that did not permit atmospheric gases to penetrate it, man-portable shields have a relatively high penetration velocity, approximately six to nine centimeters per second. However, shields for ships and planetary installations can and often do have extremely low penetration velocities, as artificial life support technologies can be utilized while the shield is active.
The interaction of a continuous wave energy beam and a Holtzman field results in subatomic fusion and a nuclear explosion. The magnitude of this blast is determined by random chance; sometimes it destroys only the shielded target and gunner, sometimes the explosion is more powerful than an atomic. Regardless of the magnitude of the blast, the gunner will always be destroyed due to feedback. Using energy weapons in a shielded environment can result in military and environmental catastrophe.
In simple terms, a shield will deflect any moving object that is moving above a critical velocity. For Personal Shields, those velocities are higher, unless the person is wearing a self contained life support unit. Above this critical velocity, the shield will deflect any moving object, no matter how small, until the shield wears down. When a shield is contacted by a continuous wave energy weapon, whether it is only used for the accelleration of a particle beam, or the actual weapon, and regardless of the EM frequency, the shield will cause a feedback that will destroy both shielded target and the firing target. This only requires the two to touch for a fraction of a second, and in this way, a shield can be used as a strategic weapon in laser-using societies.