A 58-year-old man from Delhi presents to the emergency department with sudden-onset left-sided weakness and speech difficulty. He has a history of atrial fibrillation not on anticoagulation for the past 2 years. CT head shows acute ischemic stroke in the right middle cerebral artery territory. Blood pressure is 165/95 mmHg, heart rate 102 and irregularly irregular. Which of the following best explains the pathophysiological mechanism of thrombosis in this patient?