Shield

The defensive shield, commonly called simply a shield and sometimes a Holtzman shield, was a protective energy field that could surround the person who wore it. It was an application of the Holtzman effect, drawing on the same body of physics that produced suspensor and field technologies across the Imperium. By the age of Muad'Dib the shield had become so common that anyone of even minimal importance wore a body shield, and its peculiar properties had reshaped the way wars were fought.

Operating principle#

Shields were produced by a Holtzman generator, the field deriving from the first phase of the suspensor-nullification effect. A shield could be calibrated to permit the passage of matter below a given speed, a setting that was vital for personal defense, since a wearer would suffocate inside a field that refused atmospheric gases. Depending on the calibration, an object's speed while passing through the field ranged from roughly six to nine centimeters per second. A shield could also be set to cover only the left or right side of a person when the need arose.

Shields used to protect installations could, and usually did, operate at far lower penetration velocities, because life support technologies recycled the atmosphere while the field was active. This allowed fixed defenses and ships to maintain much tighter barriers than a person on foot could tolerate.

Effect on warfare#

With the widespread use of shields, traditional firearms and directed-energy weapons were rendered largely obsolete or too dangerous to use, obliging combatants to adopt melee weapons and precise fighting styles. Shields were common enough that anyone of even minimal importance wore a body shield to protect against criminals, assassins, and accidental injury. The only reliable means of attack was the deft, careful use of a handheld dagger moved slowly enough to slip through the barrier, and new schools of fencing and knife work developed to exploit this single vulnerability. A combatant might wear a full shield, while a half-shield, such as the one used by a slave gladiator who fought Feyd-Rautha Harkonnen, was regarded as a disadvantage.

The lasgun reaction#

If a lasgun beam struck a Holtzman field, the contact produced sub-atomic fusion and a nuclear explosion. The center of the blast was determined by chance: sometimes it originated within the shield, sometimes within the laser weapon, and sometimes in both at once. This unpredictability made it suicidal to fire a lasgun at a shielded target, and the threat further entrenched the dominance of the blade. At least one commander, Duncan Idaho, deliberately exploited the phenomenon as a deterrent against his enemies.

On Arrakis#

On Arrakis a shield never lasted long, because the planet's conditions turned it into a liability. A shield could remain active only briefly, as its harmonic vibrations attracted a sandworm. A worm drawn by a shield was far more dangerous than one summoned by a thumper, because something in the Holtzman energy or in the vibrational pattern drove the creature into insane rage. For this reason the Fremen and the Atreides alike learned to do without shields in the open desert.