There are presented hollow cylindrical gas‐puff plasmas of electrical discharges at GPX device (200 kA, 40 kV, 1&mgr;s, Ne/Ar‐mixture) experimental results. Investigation of plasma with time and spatial resolution in wide spectral range was enabled by the set of diagnostics. Plasma processes were investigated in visible and IR light by frame and streak cameras, in XUV by transmission grating spectrograph and XRD, in sort X‐rays by convex and spherically bent crystal spectrograph, X‐ray crystal microscope, pin‐holes, pin‐diodes. Plasma parameters (ne = 1019–1022 cm−3,Te = 0.2–1.3 keV) were controlled by spectroscopic methods using H‐ and He‐like Ne and Ar spectra. Kink instability and hot spots were observed simultaneously in maximum X‐ray emission regimes. Also argon K&agr;line emission from plasma was observed. Plasma stabilization methods are discussed.