i sent akali silent to a battlefield with enemies, i have 6 might now, and i play a mask of foresight so she has 7 mights if i use alpha strike and target my akali how much damage i am dealing?

Yes — she deals 7 damage total, split among enemy units at battlefields.

Alpha Strike's damage is locked in when it resolves, not when you play it, so it uses her Might at that moment: 4 base + 2 from her own "when I move to a battlefield" trigger + 1 from Mask of Foresight = 7 (FAQ #9355, Rule 359.3.f.2). The targets are chosen at finalization and are capped by the damage available then — up to 7 enemy units at battlefields, each getting at least 1 — and those targets stay chosen even if the split changes later (Rule 355.14).

One thing that matters here: she's at a battlefield with enemies, so this is a Combat Showdown, and Combat Cleanup at the end of the combat heals every unit in play (Rule 468.1.a). So any non-lethal damage you split out gets wiped — only units you actually kill stay dead, though you do bank 1 XP per kill off Alpha Strike.

If you're hoping to soften up defenders before combat damage, that doesn't work; Alpha Strike is better used as reach to finish units off, or from a state where no combat cleanup follows.