The main objective of this work is to investigate the characteristics and behavior of the ion-acoustic cnoidal waves (IACWs) in an electron–positron–ion magnetoplasma having inertial positive ions with anisotropic thermal pressure and inertialess Maxwellian positrons and electrons. We utilize the reductive perturbation technique to reduce the fluid governing equations of the present model into the Korteweg–de Vries (KdV) equation in order to achieve this objective. We calculate the periodic solution of the KdV equation, also referred to as the cnoidal wave. We investigate the impact of various related parameters, including ion pressure anisotropy, positron concentrations, and temperature ratio, on the properties of IACWs. This study, particularly in the near-Earth magnetosheath and magnetosphere, may offer an insightful analysis of space and astrophysical plasma systems displaying ion pressure anisotropy.
