Something I'm noticing here is that you're trying to draw the glow as an outline. Try starting with a solid color shape like in the picture and add some brighter spots where the energy is flaring up, so to speak, rather than trying to do that!
You can add the glow in as a transparent layer later, perhaps, but there's plenty of other options.
Attempt one seems closest to what I imagine you're after, try removing the outer edge of pixels and up the saturation some!