ABSTRACT Focused drug administration is one of the most promising approaches in cancer diagnosis and treatment. By applying an external magnetic field, nanoparticles can be directed toward the tumor site, ensuring a more precise and effective therapeutic strategy. This study investigates the thermal instability of a bi‐viscous Bingham‐based nanofluidic system under the influence of an inclined magnetic field. The flow behavior is modeled using the Maxwell's equations coupled with the Navier–Stokes equations. The thermal Rayleigh number is derived through linear stability theory and normal mode analysis, enabling an examination of the effects of magnetic field orientation, nanoparticle geometry, and the intensity of a non‐uniform internal heat source on the system's thermal stability. The onset of instability is explored both numerically and analytically. Results for the limiting cases of this study are compared with previous findings and show strong agreement. It is observed that the magnetic field enhances system stability by influencing the nanoparticle trajectories. Stability increases as the magnetic field inclination deviates from the transverse direction, highlighting the potential of magnetic control in targeted drug delivery. Moreover, a transition from longitudinal to transverse rolls occurs as the magnetic field direction shifts away from the vertical orientation.
Maheshwari et al. (2026) studied this question.