(a) 171 Ĺ image showing the funnel and loop in which fast waves propagate. (b) 1600 Ĺ image showing flare ribbons. (c) 171 Ĺ base difference image showing dimming behind the CME front. The four brackets mark the smaller FOV of the other panels. (d)-(f ) 171 Ĺ running difference images showing successive wave fronts propagating in the funnel. The three curved cuts are used to obtain space-time diagrams shown in Fig. 2. The square box marks the region for Fourier analysis in Fig.4. (g)-(i) Images of (d)-(f ) in the boxed region Fourier filtered with a narrow Gaussian centered at the peak in Fig. 4(b) at frequency ν = 14.5 mHz (P = 69 s) and wave number k = 9.0 × 10-3 Mm -1 (λ = 110 Mm), which highlight the corresponding fast wave trains.

(PhysOrg.com) — Scientists using the Atmospheric Imaging Assembly (AIA) instrument on board NASA’s Solar Dynamics Observatory (SDO), have detected quasi-periodic waves in the low solar corona that travel at speeds as high as 2,000 kilometers per second (4.5 million miles per hour). These observations provide, for the first time, unambiguous evidence of propagating fast mode magnetosonic waves at such high speeds in the Sun’s low atmosphere