Résumé: X-ray emulsion chamber experiments, exposed at mountain altitude (Pamir, Chakaltaya), have exhibited some interesting phenomena around the knee region of the primary cosmic ray energy spectrum. Among these phenomena one can quote coplanar emission and halo events which are hard to explain in the framework of the standard model. In order to understand these unusual events we have performed Monte Carlo calculations using the CORSIKA code in combination with several standard hadronic interaction models such as QGSJET, DPMJET and HDPM. The main features of these remarkable events are investigated and their physical relevancy is discussed.

Résumé: X-ray emulsion chamber experiments, exposed at mountain altitude (Pamir, Chakaltaya), have exhibited some interesting phenomena around the knee region of the primary cosmic ray energy spectrum. Among these phenomena one can quote coplanar emission and halo events which are hard to explain in the framework of the standard model. In order to understand these unusual events we have performed Monte Carlo calculations using the CORSIKA code in combination with several standard hadronic interaction models such as QGSJET, DPMJET and HDPM. The main features of these remarkable events are investigated and their physical relevancy is discussed.