Magnetic and Thermal Evolution of the 1 August 2024 Coronal Mass Ejection from 10 Solar Radii to 1 AU

We investigate the radial evolution of magnetic and thermal properties of the 1 August 2024 coronal mass ejection from 10R⊙ to 1 AU. The mag netic field is modeled using an observationally constrained radial decay profile together with Ohmic and ambipolar diffusion, while the thermal evolution includes expansion cooling, radiative losses, and Alfv´enic heat ing. The combined solutions show that magnetic pressure remains domi nant over thermal pressure throughout the modeled interval, with plasma beta decreasing from approximately 0.62 near 10R⊙ to 0.13 near 1 AU. Although the proton thermal Larmor radius increases from about 0.7 km to 13 km as the magnetic field weakens, the ratio rL,p/LB remains of order 10−7, indicating strong global proton magnetization. These results sup port a collective MHD interpretation in which CME expansion weakens both magnetic and thermal energy densities while preserving large-scale magnetic confinement.