1  

Start off by making a new file with 400X400 pixels and fill your background with black color. (Note that my picture above is smaller, I'm only showing a part of my file). Make a new layer. Use an air brush with 19 pixels diameter, hard. and draw a line across your layer as illustrated.

2  

Now go ahead and duplicate that layer once, with your new layer selected go to Filter>Blur>Gaussian Blur and enter 17.0 for the blur amount, click OK. Duplicate your blurred layer and then Merge those two blurred layers together and named the new layer "Glow".

3 

With your "Glow" layer still active go to Image>Adust>Hue/Saturation...make sure the "Color" box is checked and adjust Hue so that you get red color (Note: you also have to reduce ligtness and increase saturation to get the red color).