The effect of effusion induced hydrogen instability of the superinsulation is the appearance of pressure oscillations of residual hydrogen medium in the vacuum space of the superinsulation caused by adsorption-desorption processes on metallised surfaces of the superinsulation. The genesis of these processes is caused by the occurance and the destruction of the surface states. The fluctuations of the residual hydrogen concentration can be described in the terms of birth-death processes [40]. The increase of the concentration of ionised oxygen and water in residual hydrogen medium up to the optimal level contributes to the appearance of hydrogen adsorption centres. With the water concentration in the residual atmosphere medium being increased, the destruction of these adsorption centres is observed. The desorption mechanism may be as follows: 1) surface exciton excitation, 2) volumetric exciton migration to the sample surface, 3) recombination processes of charging centres on the dispersoid surface of the SVHI dimension-quantised film.

When an effusive leak is available in the casing, the water concentration variation in the residual medium is symbate to the relative humidity variation in the ambient air [31]. The water amount being excessive in respect to the oscillatory process cycle in question is being frozen out on colder SVHI screens due to thermodiffusion through the porous screen frame.

8.1. EFFECT OF EFFUSION INDUCED HEAT CONDUCTION INSTABILITY OF THE SUPERINSULATION IN CRYOGENIC AND VACUUM FACILITIES (EIHCIS-EFFECT)

The effect is the appearance of heat conduction oscillations of the heat insulation being determined by the hydrogen concentration variations.

The hydrogen concentration in the residual medium changing in the EIHIS effect process dynamics is considered as a "thermal bridge" [6] carrying out the periodic switching of the heat flow from the cryogenic reservoir casing to the wall of the cryogenic reservoir vessel and, consequently, to the cryogenic liquid.