Speaker
Description
Coronal jets are known to be transient phenomena associated with energy release processes, with magnetic reconnection being their most probable origin. However, the precise timing and location of the reconnection events have not been clearly established. Moreover, the pronounced geometric complexity of coronal hole (CH) boundaries — where these jets typically originate — suggests a dynamic environment rich in small-scale, spatially localized structures.
To address these questions, we employed a combination of observations from the AIA/SDO instrument and the Correlation Dimension Mapping (CDM) technique. This approach enabled spatially resolved quantification of geometric irregularities along CH boundaries through the calculation of the correlation dimension.
CDM was applied to a sequence of AIA images acquired between 22:00 and 23:59UT. The images were normalized to their maximum intensity to facilitate inter-channel comparison. Edge detection was performed using an 8-point median smoothing technique with a threshold of 100DN. Fractal dimensions were calculated across various spatial scale ranges, with the 6–25 pixel interval ultimately selected due to its lower statistical uncertainties and physical relevance.
The resulting maps revealed that the boundary complexity was not homogeneous: highly structured regions were spatially localized, exhibited temporal variability, and were associated with jet evolution. When comparing these regions with the intensity profile of the 193~\AA\ channel, we observed a temporal correlation between the jet brightening and increases in the correlation dimension.
These findings suggest that CDM may serve as an effective tool for quantifying magnetic reconnection processes at the edges of coronal holes.
Additionally, we generated a CDM–time plot by calculating the correlation dimension values along the CH boundary for each AIA frame, taken every 12 seconds over the two-hour observation period. This produced a time-resolved map in which regions of high correlation dimension appeared as distinct features. By retrieving the coordinates of these high-complexity regions and mapping them back onto the CH boundary, we identified several coronal jets. These results indicate that CDM may also be employed as a tool for locating coronal jets along coronal hole boundaries.
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