'This' [Tuesday] refers to the [Tuesday] of this week. So yesterday in your example.
'Next' [Tuesday] refers to the [Tuesday] of the following week. So the 19th in your example.
If it were Monday you asked this, then it would be the same, 'This' being the 12th and 'Next' the 19th.
'Next' [Tuesday] refers to the [Tuesday] of the following week. So the 19th in your example.
If it were Monday you asked this, then it would be the same, 'This' being the 12th and 'Next' the 19th.