Can we please stop asking FFG for rule clarifications that shouldn't need to be asked if one reads the core rulebook and applies them to the card???
As noted by everyone else in this post, you spend the Target Lock to roll 4 attack dice against the defender at Range 2-3. After the 4 attack dice are modified, the defender rolls agility dice and modifies them as necessary. If there are still uncancelled "hits" and/or "crits" the defender is considered "hit" and suffers damage. So far so good???
For Ion Torpedoes, if the defender is "hit" then the defender and all ships at Range 1 of the defender receives 1 ion token.
Summary: Defender suffers all uncancelled damage AND 1 ion token; every ship at Range 1 of defender receives 1 ion token but NO damage.