  The screening of a test charge by partially degenerate non-ideal free
electrons at conditions related to warm dense matter and dense plasmas is
investigated using linear response theory and the local field correction based
on ab inito Quantum Monte-Carlo simulations data. The analysis of the obtained
results is performed by comparing to the random phase approximation and the
Singwi-Tosi-Land-Sj\"olander approximation. The applicability of the
long-wavelength approximation for the description of screening is investigated.
The impact of electronic exchange-correlations effects on structural properties
and the applicability of the screened potential from linear response theory for
the simulation of the dynamics of ions are discussed.
