Electrosurgical instruments are configured to provide increased ablative capability without requiring increased current density at the electrode. The electrosurgical instrument includes an elongate probe having a handle portion and a distal end. An electrode is disposed at the distal end and is configured to ablate tissue. The instrument includes an aspiration lumen, e.g., that may open through the electrode, at the distal end to aspirate fluid, tissue debris, and gaseous bubbles through the aspiration lumen. The electrosurgical instrument includes a user operable control (e.g., button) on the handle portion for selectively placing the instrument in boosted ablation mode, which can be achieved by restricting aspiration of fluid through the aspiration lumen, reducing active cooling of the electrode, and causing increased ablative sparking density at the electrode (e.g., by at least 10%, 20%, 35%, or 50%).
