The Surya solar model reconstructs extreme ultraviolet radiation from helium images, going back to before the SDO era

By adapting the Surya foundation model, researchers are synthesising SDO/AIA-type images from observations in the He I 10830 Å line, which have been available for much longer.

Images of the Sun in the extreme ultraviolet have only existed continuously for a few decades, while line observations of helium at 10830 Å cover a much longer period. A team adapted Surya, a foundation model trained on data from the Solar Dynamics Observatory, to produce from these helium images the equivalent of three channels of the AIA instrument (94, 193 and 304 Å), as well as a probability map of coronal holes.

Global structures rediscovered

The adaptation is based on a convolutional input adapter, low-ranking updates to the main network and dedicated decoders. On data set aside, the correlations reach 0.82, 0.89 and 0.84 depending on the channel; the segmentation of the coronal holes remains more modest (IoU of 0.44). The large structures are found, but the local detail varies greatly from one channel to another.

Applied to dates prior to SDO, a refinement module improves the resemblance with the 304 Å images of the SOHO satellite (correlation of 0.65 to 0.71). This is enough to consider reconstructing the historical solar morphology, with caution.