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We present new and archival multi-frequency radio and X-ray data forCentaurus A obtained over almost 20 years at the VLA and with Chandra, withwhich we measure the X-ray and radio spectral indices of jet knots, fluxdensity variations in the jet knots, polarization variations, and propermotions. We compare the observed properties with current knot formation modelsand particle acceleration mechanisms. We rule out impulsive particleacceleration as a formation mechanism for all of the knots as we detect thesame population of knots in all of the observations and we find no evidence ofextreme variability in the X-ray knots. We find the most likely mechanism forall the stationary knots is a collision resulting in a local shock followed bya steady state of prolonged, stable particle acceleration and X-ray synchrotronemission. In this scenario, the X-ray-only knots have radio counterparts thatare too faint to be detected, while the radio-only knots are due to weak shockswhere no particles are accelerated to X-ray emitting energies. Although thebase knots are prime candidates for reconfinement shocks, the presence of amoving knot in this vicinity and the fact that there are two base knots arehard to explain in this model. We detect apparent motion in three knots;however, their velocities and locations provide no conclusive evidence for oragainst a faster moving `spine' within the jet. The radio-only knots, bothstationary and moving, may be due to compression of the fluid.

Long Term Monitoring of the Dynamics and Particle Acceleration of Knots in the Jet of Centaurus A