Previous experiments at 0.1 TW level have shown that stability and X-ray em
ission of fast Z-pinch could be significantly improved by imploding an AI v
apor jet onto a very thin coaxial wire (Wessel et al., 1992). Here we prese
nt the first results of an Al Z-pinch using a similar liner but at mega-amp
ere level. The pinch is driven by AMBIORIX facility, a 2 TW, 0.5 Omega, 2 M
A, and a 50-ns pulse-line generator. We study the effect of an Al wire and
its diameter (20-50 mum) on the implosion dynamics, on X-ray yield, on-axis
magnetohydrodynamics (MHD) stability, and on Rayleigh-Taylor instability o
f the column at stagnation. Analysis of an Al jet on Al wire shots demonstr
ates that X-ray yield due to emission processes in the H- and He-like ioniz
ation stages (i.e., the K-shell) is enhanced, relative to the ones with Al
jet only. The wire leads also to a better symmetrization of the implosion,
and to better reproducibility of the shots. X-ray signals exhibit two simil
ar pulses, 10-ns-wide and separated by 15 ns. To discern spectrally the ori
gin of each pulse, further experiments have been performed with stainless s
teel wire (25 mum in diameter). Results show that liner and wire radiate si
multaneously and contribute to both pulses. Full analysis of a typical Al j
et on Al wire shot, using detailed collisional-radiative equilibrium (CRE)
model is given in this paper. A sketch of the pinch at stagnation, with a c
old dense core embedded in a hot low density corona, reproduces well all fe
atures of X-ray emission.