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Subject: Conventional Fusion FAQ Glossary Part 17/26 (Q)
This article was archived around: 11 Nov 1999 12:26:07 GMT
Disclaimer: While this section is still evolving, it should
be useful to many people, and I encourage you to distribute
it to anyone who might be interested (and willing to help!!!).
Glossary Part 17: Terms beginning with "Q"
FREQUENTLY USED TERMS IN CONVENTIONAL FUSION RESEARCH
AND PLASMA PHYSICS
Edited by Robert F. Heeter, email@example.com
Guide to Categories:
* = plasma/fusion/energy vocabulary
& = basic physics vocabulary
> = device type or machine name
# = name of a constant or variable
! = scientists
@ = acronym
% = labs & political organizations
$ = unit of measurement
The list of Acknowledgements is in Part 0 (intro).
# q - Variable used to indicate electric charge; also used for
the "safety factor" (see charge, safety factor). Usually clear
from context which is meant.
# Q: See Q-factor
* Q-enhancement: Refers to methods for improving the power
balance in mirror-based magnetic confinement fusion reactors.
* Q-factor: Ratio of power produced by fusion to power
put into the reactor to heat the plasma and drive the
magnetic fields. Q = 1 is the definition of scientific
breakeven, where power out = power in. Economical fusion
will require Q significantly greater than 1. Fortunately
Q increases dramatically as the plasma parameters
approach the Lawson criterion for ignition. Power to drive
the magnetic fields is frequently ignored in discussions of
Q, with the justification that a steady-state, continuous-output
fusion reactor will have superconducting magnet coils.
* Q-machine: Plasma device studied in the 1960s; noted for
its natural quiescence, which made it attractive for plasma
wave phyics experimentation.
* Q-switch: Optical switch used to rapidly change the Q of
an optical resonator (see entry for oscillator); utilized
in the optical resonator of a laser to prevent lasing action
until a high level of gain and energy storage are achieved
in the laser medium. When the switch is triggered and
rapidly increases the Q of the cavity, a stronger laser
pulse is generated.
$ Quad: Unit of energy equal to a Quadrillion BTUs (10^15)
or roughly one exajoule (see entry for joule, exajoule, BTU).
* Quasi-linear Theory: A weakly nonlinear theory of plasma
oscillations which uses perturbation theory and the random
phase approximation to find the time-evolution of the
* Quasi-neutral plasma: an ionized gas in which positive
and negative charges are present in approximately