Anomaly of microwave absorption of ice near -45$^{\circ}$C under plastic deformation

The microwave absorption of fresh ice subjected to plastic deformation when changing temperature from 0 to -60$^{\circ}$C has been measured. A decrease in the losses of radiation transmission through ice at frequencies of 32 and 125 GHz with extremum at a temperature of -45$^{\circ}$C was found. This temperature corresponds to the point at atmospheric pressure at the Widom line, which starts from a hypothetic second critical point in pressure–temperature phase space. The used measuring technique makes it possible to obtain layers of deeply supercooled water into ice and study the position of the Widom line and second critical point in phase space.