Dust-acoustic waves in strongly coupled dusty plasmas containing variable-charge impurities

A relatively self-consistent theory of dust-acoustic waves in the strongly coupled dusty plasmas containing variable-charge impurities is given. Relev ant physical proccesses such as dust elastic relaxation and dust charge rel axation are taken into account. It is shown that the negative dispersion of dust-acoustic waves due to the strong correlation of dusts is enhanced in the presence of dust-neutral collisions.