Observation of angel sprites

Abstract Angel sprites are column-like sprites, which are capped with diffuse hair regions and trailed by tendrils. This paper presents some interesting properties of the angel sprites observed in the SPRITES'99 campaign from Kitt Peak, Arizona. From the observed images, it is noted that there are faint columniform glows preceding the angel sprites, but not for other types of sprites. For the angle sprites, the top of the leading glows and the top of the tendrils roughly match in altitude, but the leading glows extend to lower altitude below the tendrils. At its brightest stage, the sprite streamers are topped with diffused hair regions and trailed by branches of luminous beads and smaller, fainter and slant side branches. These luminous beads and the side branches are the main components of the tendrils. Some sprites occurred at the same location separated in time by hundreds of milliseconds to a few minutes. In these recurrent sprite events, the earlier sprites seem to have some influence on the dynamical behavior of the later sprites.