When Luke breaks out camp his first night on Dagobah, he sets out some cases and then puts a glowing device on top of one. It looks like some sort of small heater, but someone on a forum said it was a power unit. I did a few quick searches but couldn't find anything about the prop. I did find a good screenshot, though. I've circled the device I'm asking about.
What is this small heater-looking unit supposed to be?