I can see why you're eager to close that. It looks like your screen resolution is extremely low. Are you using a netbook perhaps?
Here's the problem though: On your screen, that part looks quite large and looks empty but it's because of your screen size. I'm fairly certain it doesn't have a name and having scoured the options, I'm convinced it can't be removed. On my screen, that section contains only a few words: "Writable | Smart Insert | 423:32"
Essentially, the words that show up there are a guide for your current editing mode and location in the file. I don't think it can be turned off. If you hit Ctrl + M, it will hide almost everything possible on maximize your editor view.
On my screen, that little bar is very small. That is of course because I have a high screen resolution. If possible, try increasing the resolution on your screen to something more appropriate. You'll find you have a lot more space to code, and that little bar will become much smaller.