Ion acceleration with linearly polarized 1 petawatt (PW) intense laser pulses interacting with near critical density (NCD) gas targets was demonstrated by using two-dimensional (2D) particle-in-cell (PIC) simulations. The laser parameters considered are comfortably within the capabilities of PW laser facilities, e.g., Extreme Light Infrastructure - Nuclear Physics (ELI-NP), Shanghai Superintense Ultrafast Laser Facility (SULF) and China Academy of Engineering Physics (CAEP). PIC simulation results show that near-100 MeV proton acceleration could be stably achieved within the optimized plasma parameters range, which is a result of the Magnetic Vortex Acceleration (MVA) mechanisms and the longitudinal charge-separation field formed along the filament. Our results indicate that proton energies reaching 100 MeV, benefiting for numerous advanced applications, e.g., the treatment of proton therapy at eyes, are already accessible within the capability of currently laser facilities.