Top: Time variations of centroid shift (Δλ) and width (δλ) of the Ca XIX w line profiles (case A). The vertical dotted lines mark when each phase starts, and the vertical dashed line represents the time when heat input terminates. Bottom: Δλ‐δλ diagram. The arrows indicate the direction of time evolution. Loop orientations are θ = 0° (thick solid line), θ = 45° and ω = 0° (dot‐dashed line), and θ = 90° and ω = 90° (thin solid line).