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Multimode Quasiperiodic Pulsations in Extreme-ultraviolet Emissions Associated with an X-Class Solar Flare
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DOI：10.3847/1538-4357/ae650f.png)
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Abstract
En 中文
We report detection of quasi-periodic pulsations in extreme-ultraviolet (EUV) emissions during the peak phase of an X-class solar flare. Temporal variation of EUV intensity in 171 & Aring; and 335 & Aring; channels of SDO/AIA were analyzed using wavelet transform, Ensemble Empirical Mode Decomposition (EEMD), Hilbert-Huang spectral analysis, and Fourier techniques to investigate properties of oscillation modes. During the impulsive phase, wavelet spectra showed statistically significant power enhancements, exhibiting a dominant periodicity of 146 +/- 18 s in AIA 171 & Aring; and 186 +/- 18 s in AIA 335 & Aring;. EEMD results indicate the second and third intrinsic mode functions (IMFs) represent these periodicities too, whereas higher-order modes correspond to long-term background variations. Hilbert spectral analysis identifies periods of 117 s and 197 s in AIA 171 & Aring;, and 125 s and 194 s in AIA 335 & Aring; too, respectively. It is noteworthy that wavelet and EEMD emphasize different features, transient power versus intrinsic mode decomposition, yet their consistency in the 2-3 minute range strengthens the robustness of detected oscillatory patterns. Moreover, Hilbert spectra reveal pronounced nonstationarity and amplitude modulation, accounting for discrepancies with global Fourier estimates. Reconstructed IMFs, with cross-correlation coefficient similar to 0.9 relative to original light curves, confirm the multiperiodic nature of quasiperiodic pulsations. These findings suggest coexistence of 2 and 3 minute oscillations are intrinsic to the emission of this flare, implying the operation of multimodal processes in coronal energy release.
Keywords:
EMPIRICAL MODE DECOMPOSITION
LY-ALPHA EMISSION
STELLAR FLARES
RAY PULSATIONS
OSCILLATIONS
DYNAMICS
RADIO
RECONNECTION
LOOPS
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5.4
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8.3W
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32.0W
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