Fig. 2 | Nature Communications

Fig. 2

From: Evidence of ubiquitous Alfvén pulses transporting energy from the photosphere to the upper chromosphere

Fig. 2

Statistics of swirls detected from the SOT Ca II H line core observations. a denotes the distribution of number of swirls per frame, with b the effective radii, c the average rotating speeds at edges and d the lifetimes of all swirls. Blue (red) curves, bars and texts in the first three panels represent results of positive (negative) swirls. Black curves and texts are the results of all swirls. μ and λ in d are the expectation and maximum likelihood estimation17 of the exponential rate parameter of the lifetime, respectively. The left most bar is stripped, because lifetimes less than twice of the cadence are not measured but estimated given the limitation on the cadence. These events have also been excluded when estimating μ and λ. Source data are provided in the Source Data file

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