Given a woman who can make volumes of air into solid, impenetrable barriers, how expensive of a modern military force could such a person defeat if her power has these conditions:
- Her effect is basically forcing the air molecules / atoms / ions / whatever, to not move. So she can't filter air or anything.
- "Air" being a shorthand for any gas.
- The altered volumes of air stay where they're placed, relative to the Earth.
- The altered volumes have no visible changes, but only visible light can pass through or affect the volumes.
- When she decides to create a volume, it has to be in her sight, so if her vision is hindered, it's a bit harder, and it doesn't work in the dark.
- Created volumes can be instantaneously expand and shrunk, regardless of vision, in any direction she wishes, so long as they follow the other constraints, and is expanding into open air. If it would fail, she could still try, and will know if it fails, but doesn't know more than it failing because of intersecting an object.
- She can maintain her volumes indefinitely, even through sleeping, but not if rendered unconscious through sleeping gas or other methods.
- The total volume altered must be no larger than 10m³, otherwise, she has to revert some areas to keep her changed volumes, under that limit.
- Any individual section has a thickness of at least 1mm.
- Anything hitting the "forcefield" has no effect. It's just magically stopped, you can't strain her by hitting the field too much, it doesn't turn all kinetic energy into visible light, nothing, just stopped.
The forces are surprised by each other, with the military force initially thinking she's a normal human, and hopefully, they figure out that she's making the barriers.
Inexplicably, hostilities start in the morning, on an open, grassy plain, in calm weather. Behind each party are mountains.
She has no allies.
Hostilities stop once one side is dead or incapacitated.
The forces start one mile apart.
The superpowered woman can use weaponry they acquire from defeating the forces against her.
Technology is constrained to that which is available to 2016 America.
So, how expensive must that army be, in order to defeat a woman with such powers?
Expense is calculated in the cost of equipment and the amount of training required to use that equipment to the required skill level