Imaging the Global Distribution of Plasmaspheric Oxygen

This paper investigates the potential for 83.4 nm imaging of the plasmaspheric dense oxygen torus, using simple models for core plasma density and composition to constrain a simulated image code. We derive the requirements for plasmaspheric O⁺ imaging, and the expected performance of an imager based on a slightly modified version of the IMAGE extreme ultraviolet camera. We find that such an imager can achieve a sensitivity of 0.69(s R pixel)⁻¹, sufficient to capture the dense torus 83.4 nm signal with 25 min integration time. The background rejection ratios for this design are 1.5 × 10⁻⁴ at 58.4 nm and 7.4 × 10⁻⁸ for Lyman-α. We discuss the effects of ion temperature and motion, and O⁺⁺ glow. We compute simulated O⁺ images of the formation and global distribution of the dense torus. We also examine the possibility of direct observation of oxygen outflow from the ionosphere.