Converging Luminosity in Column-Sprite Filaments

<p>Sprites are electrical discharges in the mesosphere powered by the quasi‐electrostatic field following a cloud‐to‐ground lightning stroke. They are luminous structures with tendrils formed by a space charge wave with high electric fields that ionizes the atmosphere, excites optical emissions and leaves a trail of enhanced densities of electrons, and negative and positive ions. The duration of the luminous streamers in sprites is usually &sim;1&ndash;10&nbsp;ms. In this study, we present observations of sprite streamer filaments where the upper and lower ends continue to glow for more than 80&nbsp;ms while the two ends slowly converge and fade. Simultaneous magnetic observations suggest that the field in the mesosphere is maintained at a high value by the long‐lasting continuing current of the causative stroke. We propose that the observation is a signature of currents in the filaments fed by electrons detached from negative ions at the lower origin.</p>