Influence of plasma fluctuation on the electronic structures and electron collisional excitation and ionization processes

•A fully relativistic approach is proposed/suggested to precisely predict the electronic structures and collision processes.•The present method incorporating the plasma fluctuation is applied to the He-α (1s2p→1s2) line shift of Al11+ ions.•The present work not only contributes an insight into the plasma shielding effect in extreme conditions, but also has important applications in laboratory and space plasmas.