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Abstract We present a novel hybrid forecasting strategy combining numerical, statistical, and machine learning–based forecasting to detect the occurrence of the next enhanced solar activity bursts. These enhanced bursts are called “space weather seasons,” which occur on intermediate timescales (6–18 months). Monthly smoothed sunspot number (SSN) data from 1878 to 2025 are analyzed using Gaussian fitting techniques to identify burst events and their properties such as amplitude and duration. The SSN data are divided into training, test, and forecast, which shows hindcast and forecast. Each hemisphere is modeled via a seasonal autoregressive integrated moving average approach, refined with an asymmetric Gaussian override to capture rapid burst rise and gradual decay, and burst amplitudes and duration are predicted using a random forest regression model. This hybrid approach successfully hindcasts burst timing in between 2024 November and 2025 May, with a peak SSN of ∼70 around 2025 March for the Northern Hemisphere. The next burst in the Northern Hemisphere is forecast to be in 2025 December with a slightly lower SSN of 60. By contrast, the Southern Hemisphere shows relatively complicated behavior, where the bursts show multiple amplitudes starting approximately in 2024 October and ending in 2025 October. The main burst shows an amplitude of 130 SSN. The next burst in the Southern Hemisphere is forecast to occur approximately in 2025 December. Combining SSN properties in both hemispheres, we find that the total SSN is mainly influenced by a stronger cycle in the Southern Hemisphere. 

ABSTRACT We present the first observations of chromospheric swirls using the Hydrogen-alpha Rapid Dynamics camera and Rapid Oscillations in the Solar Atmosphere imaging instruments at the Dunn Solar Telescope. These vortices contribute to heating and dynamics across the solar atmosphere. We analyse the morphology and evolution of 34 swirls and their cospatial bright points (BPs) from the photosphere to the mid-chromosphere. To examine swirl–BP interactions and temporal behaviour, we use image segmentation, Fourier and spectral analysis, and local correlation tracking. The observed swirls have an average lifetime of 7.9 $$\pm$$ 5 min and diameter of 3.6 $$\pm$$ 1 Mm, with a positive correlation indicating smaller swirls tend to be short-lived. 76 per cent are associated with a compact BP appearing 12 s to 9 min after swirl formation. Swirl motion is also closely linked to their BP(s) global motions. The swirls exhibit a mean angular speed of 0.04 rad s$$^{-1}$$, radial speed of 17.7 km s$$^{-1}$$, and period of 180 s. We observe the formation of a spiral-shaped swirl driven by a BP interacting with a large photospheric vortex. The BP is dragged towards the vortex centre, after which the swirl forms. The BP undergoes changes in orientation and elongation that mirror the swirl’s chromospheric development. A time lag of $-42.5$ s between the sudden change in the BP’s orientation and the peak of the swirl’s intensity variation suggests torsional Alfvén waves may contribute to swirl evolution. Our results support a magnetic origin for swirls rooted in motions of photospheric BPs. 

Abstract The Sunspot Solar Observatory Data Archive (SSODA) stores data acquired with the suite of instruments at the Richard B. Dunn Solar Telescope (DST) from February 2018 to the present. The instrumentation at the DST continues to provide high cadence imaging, spectroscopy, and polarimetry of the solar photosphere and chromosphere across a wavelength range from 3500 Å to 11,000 Å. At the time of writing, the archive contains approximately 374 TiB of data across more than 520 observing days (starting on February 1, 2018). These numbers are approximate as the DST remains operational, and is actively adding new data to the archive. The SSODA includes both raw and calibrated data. A subset of the archive contains the results of photospheric and chromospheric spectropolarimetric inversions using the Hazel-2.0 code to obtain maps of magnetic fields, temperatures, and velocity flows. The SSODA represents a unique resource for the investigation of plasma processes throughout the solar atmosphere, the origin of space weather events, and the properties of active regions throughout the rise of Solar Cycle 25. 

ABSTRACT New instruments and telescopes covering the optical and ultraviolet spectral regions have revealed a range of small-scale dynamic features, many which may be related. For example, the range of spicule-like features hints towards a spectrum of features and not just two types; however, direct observational evidence in terms of tracking spicules across multiple wavelengths is needed in order to provide further insight into the dynamics of the Sun’s outer atmosphere. This paper uses H α data obtained with the CRisp Imaging SpectroPolarimeter instrument on the Swedish 1-m Solar Telescope, and in the transition region using the Interface Region Imaging Spectrograph with the SJI 1400 Å channel plus spectral data via the Si iv 1394 Å line to track spicules termed rapid blueshifted excursions (RBEs). The RBEs as seen in the H α blue wing images presented here can be subdivided into two categories: a single or multithreaded feature. Based on the H α spectra, the features can be divided into events showing broadening and line core absorption, events showing broadening and line core emission, events with a pure blueshifted H α profile without any absorption in the red wing, and broadened line profile with the absorption in the blue stronger compared to the red wing. From the RBE-like events that have a Si iv 1394 Å line profile, 78  per cent of them show a Si iv line flux increase. Most of these features show a second broadened Si iv component that is slightly blueshifted. 

ABSTRACT We show signatures of spicules termed rapid blueshifted excursions (RBEs) in the Si iv 1394 Å emission line using a semi-automated detection approach. We use the H α filtergrams obtained by the CRISP imaging spectropolarimeter on the Swedish 1-m Solar Telescope and co-aligned Interface Region Imaging Spectrograph data using the SJI 1400 Å channel to study the spatiotemporal signature of the RBEs in the transition region. The detection of RBEs is carried out using an oriented coronal loop tracing algorithm on H α Dopplergrams at ±35 km s−1. We find that the number of detected features is significantly impacted by the time-varying contrast values of the detection images, which are caused by the changes in the atmospheric seeing conditions. We detect 407 events with lifetime greater than 32 s. This number is further reduced to 168 RBEs based on the H α profile and the proximity of RBEs to the large-scale flow. Of these 168 RBEs, 89 of them display a clear spatiotemporal signature in the SJI 1400 Å channel, indicating that a total of $$\sim 53{{\ \rm per\ cent}}$$ are observed to have co-spatial signatures between the chromosphere and the transition region. 

Abstract We investigate high-resolution spectroscopic and imaging observations from the CRisp Imaging SpectroPolarimeter (CRISP) instrument to study the dynamics of chromospheric spicule-type events. It is widely accepted that chromospheric fine structures are waveguides for several types of magnetohydrodynamic (MHD) oscillations, which can transport energy from the lower to upper layers of the Sun. We provide a statistical study of 30 high-frequency waves associated with spicule-type events. These high-frequency oscillations have two components of transverse motions: the plane-of-sky (POS) motion and the line-of-sight (LOS) motion. We focus on single isolated spicules and track the POS using time–distance analysis and in the LOS direction using Doppler information. We use moment analysis to find the relation between the two motions. The composition of these two motions suggests that the wave has a helical structure. The oscillations do not have phase differences between points along the structure. This may be the result of the oscillation being a standing mode, or that propagation is mostly in the perpendicular direction. There is evidence of fast magnetoacoustic wave fronts propagating across these structures. To conclude, we hypothesize that the compression and rarefaction of passing magnetoacoustic waves may influence the appearance of spicule-type events, not only by contributing to moving them in and out of the wing of the spectral line but also through the creation of density enhancements and an increase in opacity in the Hαline.