Posted by During the week of May 8 – 15, 2024, the active region AR13664 on the Sun unleashed numerous X-class and M-class flares, accompanied by Coronal Mass Ejections (CMEs) on May 8 and 9. This culminated in a significant geomagnetic storm on May 11, 2024. Aditya-L1’s remote sensing payloads, SoLEXS and HEL1OS, captured these events on May 8-9, while the in-situ payloads, ASPEX and MAG, recorded them on May 10-11 as the spacecraft passed through L1. ISRO, along with Chandrayaan-2, XPoSat, and the USO-PRL ground-based facility, reported these observations.
Unfortunately, Aditya-L1’s Solar Ultra Violet Imaging Telescope (SUIT) and Visible Emission Line Coronagraph (VELC) were in baking and calibration modes respectively during May 10-11, but resumed observations on May 14 after completing their intended operations.Observations by Chandrayaan-2, XPoSat, and ground-based facilities supported these findings.
SUIT Observations.
SUIT (Solar Ultra Violet Imaging Telescope) captured images of the Sun in various narrow and broad UV bands:
Figure 1: Mg II k line (NB3): Highlights bright, active regions on the solar disk.
Sun in Mg II k Line (NB3) : This image captures the Sun’s active regions in the Mg II k line, highlighting bright spots on the solar disk. These regions indicate areas with intense magnetic activity, often the origin of large solar flares due to magnetic field variations. As the Sun approaches its solar maximum, increased activity is evident, particularly around the equator.
Figure 2: Mg II h line (NB4): Shows similar active regions as NB3.
Sun in Mg II h Line (NB4): The NB4 image highlights bright, active regions on the Sun, indicating magnetically active areas. These regions are potential origins for solar flares due to magnetic field changes. As the Sun moves towards its solar maximum, increased activity is visible, especially around the equator.
Figure 3: Narrow Band 276 nm (NB2): Reveals sunspots and plages.
Sun in Narrow Band 276 nm (NB2): This image shows continuum emission highlighting sunspots in active regions and surrounding plages, indicating areas of intense solar activity.
Figure 4: Narrow Band 283 nm (NB5): Differentiates sunspots and magnetic structures at varying atmospheric heights.
Sun in Narrow Band 283 nm (NB5): This image shows sunspots and plages in active regions, with brightness variations different from the 276 nm band. This difference arises from the narrow bands probing different atmospheric heights, revealing structural differences in magnetic tubes.
Figure 5: Narrow Band 300 nm (NB6): Displays sunspots with distinct umbra and penumbra.
Figure 6: Broad Band 320-360 nm (BB3): Probes UV continuum emission from the chromosphere.
Sun in Broad Band 320-360 nm (BB3): This image probes the UV continuum emission from the chromosphere, covering a wide range of depths in the solar atmosphere. It prominently displays sunspots on the disk and limb.
Figure 7: VELC Observations.
VELC (Visible Emission Line Coronagraph) performed raster scans of the solar corona on May 14, 2024, capturing activities at 5303 Angstrom . The image highlights the location of AR 13664, showing detailed coronal structures while blocking the bright light from the solar photosphere.
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| VELC observations made on May 14, 2024, at 5303 Angstrom. AR 13664 location is marked in this raster image as a box. |
VELC Observations in 5303 Ångström: On May 14, 2024, VELC conducted raster scans of the solar corona in the 5303 Ångström emission line. The resulting image captures coronal activities, with the AR 13664 location marked. The scan, assembled from wavelength-averaged slit images, took about 20 minutes using four slits to cover different regions simultaneously. The yellow open circle marks the solar photosphere edge, while the black filled circle indicates the occulting disk used to block bright light from the photosphere, revealing faint coronal structures.
