  We argue that the dielectric effect, mostly studied for systems of coincident
D-branes, is also extendible to configurations of multiple gravitational waves.
We provide some evidence that Matrix string theory has an alternative
interpretation as describing also, in the static gauge, multiple Type IIA
gravitational waves. Starting with the linearised action of Matrix string
theory in a weakly curved background, we identify the non-Abelian couplings of
multiple coinciding gravitons to weak background fields, both in Type IIA and
in Type IIB, and we use them to study various dielectric configurations from
the point of view of the expanding gravitons. We also identify, in the Abelian
limit, some non-perturbative correction terms to the Abelian gravitational wave
action.
