What is sonnengewehr?

As an AI language model, I don't have access to any specific information about "Sonnengewehr". However, the word "Sonnengewehr" is a German word that translates to "solar rifle" or "sun gun" in English. The concept of using solar power as a weapon has been explored in science fiction literature and movies, but it has not been developed into a practical weapon in real life. Therefore, any information about a real "Sonnengewehr" would be purely speculative or fictional.