The Plasma and Field Perturbation Around a Charged Dust Cloud in the Solar Wind

Abstract:

When asteroids and meteoroids collide at their typical speeds of 20km/s at 1AU, they can totally disrupt each other if their mass ratios are within a factor of 10⁶. The resulting charged dust and gas can be picked up by the solar wind, resulting in a large magnetic structure containing over 10⁶kg of mass, accelerated to almost the solar wind speed. This dust is invisible to our Earth-based detectors as are the impactors and targets but they can be detected by our interplanetary spacecraft and they do create ground-level magnetospheric disturbances when they impact the Earth. Moreover we can identify the parent bodies for these impacting bolides by determining which asteroids cross the ecliptic plane along the path of these disturbances carried by the solar wind. Hence, these structures can be used in a planetary defense strategy. Since they have a very practical application we need to understand their formation and evolution better. We apply our multi-fluid code to model this interaction, to show how the field is affected by charged dust. We assume a cloud of charged dust moving close to the solar wind speed, but a small velocity difference exists between the dust and ions. Gravity pulls horizontally opposite to the solar wind plasma, maintaining the concentration of dust cloud.