Sastrugi sea ice than on multiyear ice. First-year ice is smoother than multiyear ice, which allows the wind to pass uniformly over the surface without topographic obstructions. Except during the melt season, snow is dry and light in climates cold enough for sea ice, allowing the snow to be easily blown and create sastrugi parallel to the wind direction. The locations of sastrugi are fixed by March in the northern hemisphere and may be linked to the formation of melt ponds. Melt ponds are more likely to form in the depressions between zastrugi on first-year ice. Sastrugi Sastrugi, or zastrugi, are
Surface-wave-sustained mode the generation of high density plasmas. Electromagnetic waves cannot propagate in over-dense plasmas. The wave is reflected at the plasma surface due to the skin effect and becomes an evanescent wave. Its penetration depth corresponds to the skin depth formula_1, which can be approximated by The non-vanishing penetration depth of an evanescent wave opens an alternative way of heating a plasma: Instead of "traversing" the plasma, the conductivity of the plasma enables the wave to propagate "along" the plasma surface. The wave energy is then transferred to the plasma by an evanescent wave which enters the plasma perpendicular to its