Solar protuberances can be of three types: (1) loop-shaped; (2) normal to the visible solar surface; (3) initially parallel to the solar surface and then going away normally to it. For example, the protuberance of June 4, 1946 was of the third type.
A short description of this protuberance is available by the address:
http://www.prosto-o-slognom.ru/astronomia/28.html. This description is given there in Russian and is translated by me. “One of the largest solar protuberances was observed on June 4, 1946. At first, it had a form of a giant pulsing arch that extended for 700 000 km that is a half of Sun's diameter. Then, this protuberance quickly shot up above the chromosphere before the amazed astronomers' eyes and reached a height of 1 700 000 km! This height exceeds the Earth–Moon distance by a factor of 4.4.”
The detailed NASA information in English is available by the address:
http://iopscience.iop.org/article/10.1086/125856/pdf in the paper by Pettit E., where Fig. 1 gives the scheme of the protuberance moving (Pettit E., “An Eruptive Prominence of Record Height, June 4, 1946”, Publications of the Astronomical Society of the Pacific, Vol.58, No.344, p.310-314).
What are the physical causes of each type of solar protuberances?