Non-perturbative QCD measurements in ATLAS

We present results on the characteristics of the charged particle production in proton-proton collisions collected at the Large Hadron Collider at the center of mass energies of sqrt(s) = 900 GeV and 7 TeV in the ATLAS Detector. Charged tracks are measured with high precision in the inner tracking system. Track multiplicities and transverse momentum distributions are used to study the characteristics of soft interactions and Underlying event. These data can then be used in the tuning of the Monte Carlo models used to describe the non-perturbative part of the event to obtain more reliable predictions. The analysis dedicated to study the non-pertubative part of the events will be discussed and the results obtained so far will be shown. We will also show the results of the improved data description obtained with the new tuning of the Monte Carlo models.