I have a character that can create compressed air spheres. If you were to create just a normal sphere of compressed air, it would expand in all directions equally at a speed and force that would depend on how compressed you made the air. While that certainly can be useful under the right circumstances, its far more useful to be able to focus the air burst in a specific direction. Here are the limitations:
- When it comes to creating air, this means he has the ability to create any molecular structure that's a gas at room temperature and it is created at room temperature - though note that the more unnatural the gas is, the harder it is for him to create. Oxygen is fine, sulfur hexalfuoride can only be created in limited amounts.
- The character uses a magic ability to create air within a six-inch sphere of his choosing. The sphere is created at chest level about a foot in front of him. He can choose where any air is added within the sphere - for instance, he can add extra oxygen to the left side and nitrogen to the right if he so chooses.
- He cannot destroy air or move it - his ability is restricted to creating it. He can't have one side of the sphere be a vacuum, for instance, or do anything about the normal atmospheric air that's already in the sphere.
Given these restrictions, I thought it might be possible to create something resembling a 'shaped wind charge' - when crafting the sphere, the character uses a highly-compressed glob of lighter air, surrounded by a not-as-compressed shell of heavier air which serves to dampen the expanding lighter air and focus a blast in one direction.
The three limitations cannot be violated, though if it can only be done with large amounts of rare gasses, it is what it is. Tools (i.e. a gun facsimile) are not allowed, the goal is to do this using created wind only. So, the question is: what's the optimal gasses to use for such a shaped wind charge, and how effective will that end up being?
There is a hard-science tag applied to the question because I want very specific gasses.