The electrical effects of micrometeoroids entering the terrestrial atmosphere at different speeds†

Micrometeoroids entering the terrestrial atmosphere lead to two important related electrical effects. One is the electrification of the upper atmosphere along their paths and the other is the electrical charging of the micrometeoroids themselves. In this brief note we will emphasize the central role of the initial encounter speed of the incoming micrometeoroid, showing how it changes the altitude profiles of electron production and electrical charging, not just quantitatively but also qualitatively. We will discuss the underlying reasons for this, as well as their importance in meteor studies.