Arcane Ward

A 1/4 inch thick shimmering dome of energy springs into existence from your hands. The dome is hemispherical with a 20 ft radius. Choose a direction you wish to cast the spell, whichever direction you choose is where the center of the dome is. This spell can be used as a Bonus Action or Reaction, and can be held up as long as you can hold concentration and have a free hand. If the wall cuts through a creature's space when it appears, the creature is pushed to one side of the wall (your choice which side).

Nothing can physically pass through the dome. The dome has an initial health pool of 11 (or 2d10) hit points. Whatever damage goes beyond that health pool goes into whoever or whatever the ward was protecting. However, when your ward hits 0 hit points, you may expend a spell slot to keep the ward stable. When doing so, reroll the standard health pool, and the spell slot you use determines how much additional health the stabilized ward has.

When you cast this spell using a spell slot of 2nd level or higher, roll an additional 2d10 or 11 for each slot level above 1st and add it to the ward's health pool.