You're triggering Centering. This is gained at level 10 as a Jedi Sentinel (so it is Sentinel specific).

You gain stacks of Centering whenever you spend focus or kill an enemy, and it doesn't do anything on its own until you reach 30 stacks of the buff. At that point, you can trigger Zen, Transcendence, or Inspiration:

• Zen - learned at level 10. Gives a bonus depending on your current lightsaber form.
• Transcendence - learned at level 22. Temporary Movement and Ranged Defense Bonuses for you and your party.
• Inspiration - learned at level 44. Gives a % damage bonus to you and your party.

You're triggering Centering. This is gained at level 10 as a Jedi Sentinel (so it is Sentinel specific, though Sith Marauders have an equivalent ability).

You gain stacks of Centering whenever you spend focus or kill an enemy, and it doesn't do anything on its own until you reach 30 stacks of the buff. At that point, you can trigger Zen, Transcendence, or Inspiration:

• Zen - learned at level 10. Gives a bonus depending on your current lightsaber form.
• Transcendence - learned at level 22. Temporary Movement and Ranged Defense Bonuses for you and your party.
• Inspiration - learned at level 44. Gives a % damage bonus to you and your party.