Clustering of Ions at Atomic Dimensions in Quantum Plasmas
  By means of particle simulations of the equations of motion for ions interacting among themselves under the influence of newly discovered Shukla-Eliasson attractive force (SEAF) in a dense quantum plasma, we demonstrate that the SEAF can bring ions closer at atomic dimensions. We present simulation results of the dynamics of an ensemble of ions in the presence of the SEAF without and with confining external potentials and collisions between the ions and degenerate electrons. Our particle simulations reveal that under the SEAF, ions attract each other, come closer and form ionic clusters in the bath of degenerate electrons that shield the ions. Furthermore, an external confining potential produces robust ion clusters that can have cigar-like and ball-like shapes, which remain stable when the confining potential is removed. The stability of ion clusters is discussed. Our results may have applications to solid density plasmas (density exceeding $10^{23}$ per cubic centimeters), where the electrons will be degenerate and quantum forces due to the electron recoil effect caused by the overlapping of electron wave functions and electron tunneling through the Bohm potential, electron-exchange and electron-exchange and electron correlations associated with electron-1/2 spin effect, and the quantum statistical pressure of the degenerate electrons play a decisive role. 
P. K. Shukla and B. Eliasson
physics.plasm-ph