GONG data processing update

Processing of the network-merged daily velocity and magnetogram images, p-mode-coefficient time series, and ring-diagram analysis products for GONG month 306, and the p-mode frequency data products for central GONG month 305 is completed and the data products are now available.

next-generation Ground-based Solar Observing Network

NSO has issued a press release announcing receiving funding from NSF to Design the Next-Generation Solar Observing Network to Advance Solar Science and Space Weather Forecasting.

The U.S. National Science Foundation National Solar Observatory (NSF NSO) will receive $19 million for design work for the Next-Generation Ground-based Solar Observing Network (ngGONG), a state-of-the-art solar observing network that will provide multi-decade, 24/7 monitoring and observing of the Sun.

ngGONG will be capable to:

• Provide continuous measurements of the Sun to study the processes driving solar activity from the Sun’s interior through the heliosphere, improving our understanding of solar structure and space weather.
• Deliver critical quantitative context for high-resolution solar and in-situ measurements, as well as advanced modeling efforts.
• Bridge solar and stellar research, shedding light on the impacts of stellar activity on planetary habitability both in our solar system and beyond.
• Serve as a platform for instrument innovation and long-term scientific discovery, creating a multi-decade record of solar variability for future generations of researchers.

The official award is now listed at NSF.gov. 

 

AGU calls for nominations of impactful datasets

Recently,  the American Geophysical Union (AGU) called for nominations of impactful datasets. It is highlighting and celebrating datasets that support the broad spectrum of research, analysis, and decision making by Earth and space sciences communities. AGU is looking for the impacts in three dimensions: people, planet, and prosperity. Nominations are due October 10th!For complete details and to submit your nomination see http://lite.spr.ly/6009zklz. 

 

 

 

 

 

New Ceph cluster for NISP data storage

Work has started on replacing the current NISP Isilon cluster by a new Ceph cluster for data storage. Last week, the base hardware for a "sandbox" (test) cluster was successfully installed and tested (see figure on the right).  The testing will continue as the main cluster is built. The plan is to complete the transition to the new cluster by the end of FY2026. The new cluster will increase the storage space available for NISP observations by approximately 50%, which include GONG, SOLIS, and legacy observations from various NSO and non-NSO instruments.

Update on the GONG/TD LCVR temperature control issue

This is an update on the note about GONG/Teide (TD) site (Canary Islands, Spain) LCVR temperature control issue, posted back in July. Once the LCVR temperature controller was disabled on June 24th, the TD-EVT data has been stable. Science tests of the TD Doppler velocity and magnetic field images before and after the LCVR temperature control was turned off did not uncover any significant problems with the data. The GONG/TD-EVT images have been accepted for downstream processing.

GONG refurbishment project update

NISP Data Center, scientists, and engineers completed vetting tenth GONG EVT (Emergent Vision Technologies) camera in frame of the GONG refurbishment project. This camera will upgrade one of the engineering sites in Boulder.  

Recurrent geomagnetic storms

Recurrent geomagnetic storms are associated with large coronal holes (CH). As Sun rotates, the same area of open magnetic field is brought up to face Earth every about 26 days. A large CH that was observed crossing solar central meridian early this week existed for several solar rotations. Upper row of images show solar corona observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) on 19 June, 15 August, and 11 September 2025. A large CH is seeing near central meridian on these days. In all cases, about four days later, there were moderate geomagnetic storms associated with this CH. Lower panel shows Kp (ap) index from the International Service of Geomagnetic Indices (ISGI)  database. It appears that a geomagnetic storm associated with this CH is now in development. 

GONG supports Parker Solar Probe's 25th encounter

Parker Solar Probe is approaching its 25th encounter, with perihelion expected on September 15 at 20:22 UT. The magnetic connectivity prediction issued on 12 Sep 2025 includes modeling predictions based on GONG magnetic field observations. For image on the right - Helioprojective PSP predicted footpoints: one footpoint per day plotted on the solar disk. Colored dots show predictions from a range of models. Gold squares show the consensus value for each day. Black contours show the full width half maximum for the Kent distribution (en.wikipedia.org/wiki/Kent_distribution) fitted to each set of footpoints (Courtesy of Sam Badman). This is the first of seven updates (for future updates see here).

UPDATED: Large coronal hole is crossing solar central meridian - when we will see a geomagnetic storm?

 A large coronal hole that was described earlier  is now crossing solar central meridian. High-speed solar wind streams (HSSs) originating in coronal holes may have velocities as high as 800 km/s, and reach Earth in about 2 days. Disturbance storm time (Dst) index is used to measure the impact of solar activity on Earth environment. A moderate geomagnetic storm has Dst index between -50 nT and -100 nT. Dst can be predicted from the magnetic field (polarity) associated with the coronal hole and the velocity of HSS. The later could be estimated from area of CH. Using this approach (see Nitti et al, 2023, doi: 10.1093/mnras/stac3533) one could expect to see a moderate-strength geomagnetic storm associated with this CH in about 2-3 days. Negative polarity magnetic field associated with this CH measured by GONG suggests stronger geomagnetic storm as compared with positive polarity field. Let's wait and see ... 

UPDATED on 14 Sep 2025: 

The Wang-Sheeley-Arge (WSA) model of solar wind predicts Earth entering HSS originating from this CH on about 14 Sep 2025, and reaching its middle point on 16 Sept 2025.  A snap-shot of  NOAA's WSA–Enlil model on the right shows predicted plasma density (top) and radial velocity (bottom) across the inner solar system. The sun is at the center (yellow), Earth is green, and STEREO A is red. As an input parameter, WSA-Enlil uses GONG magnetograms. Image credit: NOAA Space Weather Prediction Center.

It seems, the geomagnetic storms associated with this CH is now in development.  

Chromospheric H-alpha surge as observed by GONG

On 9 September 2025, GONG/Learmonth station captured H-alpha  surge (H-alpha jet) in a close proximity to the main sunspot of active region 14207. H-alpha jets appear as eruptions along narrow collimated path. The surges are accompanied by micro-flares at its base, followed by the eruption of a dark material. Some surges show rotational motions. The surges are modeled as a reconnection events between the opened magnetic fields and closed magnetic fields of emerging regions (see below for magnetic field configuration by Yuandeng Shen (2021, doi: 10.1098/rspa.2020.0217)).  Small-scale solar jets play an important role in supplying material and energy to the solar wind. Larger jet may contribute to space weather.

 

 

Large coronal hole and future space weather event?

Solar magnetic fields usually come in pairs: active regions have two opposite polarities, similar to bar magnets. One can identify some of these bipolar structures in a solar magnetogram from GONG on the right with positive/negative polarity fields shown as white/black halftones. Sometimes, the patterns are more complex with multiple positive and negative polarities.  Magnetic flux in these twin or multi-polarity regions is usually well-balanced: magnetic field lines originating in one polarity connect to the opposite polarity in the same active region or its surroundings. Corona is bright above closed magnetic field areas (active regions, see SDO/AIA image on far right). There are, however, areas which have predominantly single polarity magnetic field. Magnetic field lines originating in these unipolar areas may not connect to the solar surface, but extend to the interplanetary space. These areas of opened magnetic field coincide with coronal holes, areas were the corona appears much darker. One of these large coronal holes is now crossing solar visible disk. Coronal holes are associated with streams of fast solar wind, which cause moderate geomagnetic storms. We should expect a moderate geomagnetic storm activity in several days after the corona hole passes solar central meridian. 

Rare "double-decker" filament eruption

Traditional model represents the chromospheric filaments as dense, cold (relative to its surroundings) material seating in the lower part of horizontal magnetic flux tubes. In this model, the magnetic forces support the filament material against gravity, keeping it from falling down to the solar surface. The model explains many properties of filaments including their relation with the coronal mass ejections. However, the magnetic flux tube is continuous structure, and when the filament erupts, it is expected that the entire flux tube erupts with it. There are, however, instances when only a portion of filament material erupts leaving other part intact. Such filament splitting was explained in the framework of so-called double-decker filaments, when the magnetic reconnection results in splitting of magnetic flux tube into two separate tubes. A filament eruption on 6 September 2025 at 14:51 UT observed by GONG at Cerro Tololo, Chile  captured the filament splitting into two separate filaments. There are some small flare-like brightennings, but no X-ray class flare.  Also, no CME was associated with this event, and so, this is a failed filament eruption. These observations provide a strong support for the double-decker filament model. See for yourself.

What is a double-decker filament?

It refers to two separate filaments situated above the same polarity inversion line. Rui Liu et al (2012, doi:10.1088/0004-637X/756/1/59) proposed two magnetic configuration of a double-decker filament: (a) the upper and lower branches are flux ropes, (b) the upper branch is the flux rope and the lower one is the sheared arcade. Such configuration allows the eruption of one of the filaments, without impacting the other filament.  The filament eruption could be triggered by a loss of equilibrium due to flux imbalance, the torus or kink instabilities. Sunspot rotation was observed prior to some double-decker filament eruptions. More recent studies (e.g., Dongxu Liu et al 2025, doi: 10.3847/2041-8213/addfca) provide support to torus instability as a trigger for the filament eruption.

UPDATED: New data product in development: GONG H-Alpha Integral Carrington synoptic maps

NISP group is seeking feedback on a new data product currently in development: GONG H-Alpha integral Carrington synoptic maps. We are especially interested in suggestions regarding the appropriate set of keywords to include in the FITS file headers, as well as comments on the current map format.

At present, the maps are provided in Carrington sin(latitude)–longitude coordinates, with a resolution of 360 × 720 pixels. Observations from selected GONG sites are corrected for limb darkening and uniformly scaled in intensity before being merged into the final synoptic map.

A selection of FITS files is available at the following link: https://drive.google.com/drive/folders/1M0ZwpBA_SW8JuMwlDP0Se75M2IQkCGQ3?usp=sharing

Please email your comments to nispdata@nso.edu by 15 October 2025.

C-class two-ribbon flare with filament eruption

 

On 4 September 2025 at 19:10 UT, C3.4 class flare erupted from NOAA active region 14206. The flare was captured by GONG station at Cerro Tololo, Chile. A portion of an active region filament situated near the main sunspot of this region starts slowly rising about 30 minutes before the eruption. After the eruption,  dark filament material can be seen in a low part of image as material is leaving the Sun. After the filament erupts, two bright ribbons develop, moving apart from the past filament location. This is a classical two-ribbon flare, which is usually accompanied by a coronal mass ejection (CME). The eruption took place near the solar central meridian, and if it was a CME, it would likely be Earth-directed. In this movie  created with different image scaling, one can briefly see a dark circular front centered at the eruption site (see image below). This is a signature of the Moreton (blast) wave, which maybe another indication of CME.  Unfortunately, LASCO C3 coronagraph has about 4 hour gap in observations between 16:54 UT and 21:06 UT, and thus, similar to previous event, it is not clear if it was a CME or not.

 

 

 

Blast from the past

 In August 1972, a series of solar flares and associated geomagnetic storms led to widespread communications disturbances and power outages. On August 4th, the geomagnetic storm caused a nearly instantaneous detonation of dozens of sea mines installed by the US during the Vietnam War south of Hai Phong. The August 4th flare, which occurred between the Apollo 16 and Apollo 17 missions, led to a significant increase in the radiation level in the interplanetary space. It was estimated that for the astronauts on the moonwalk, the radiation dose equivalents would have been clinically significant, including nausea, vomiting, a very high probability of cataract formation, with a slight increase in the probability of death. This flare, which occurred more than 50 years ago, was well-observed by the H-alpha flare patrol telescope at the National Solar Observatory at Sacramento Peak. Image on the left shows the Sun before the flare, and on the right is the flare in progress. You can also see that a portion of filament left of the flaring region had disappeared. These are the signs of a coronal mass ejection erupting from this area of the Sun. Study of the past events may bring invaluable information  about how such strong eruptions develop and help us to prepare for traveling to the Moon and Mars.

GONG Big Bear station

Broadband image from GONG/BB

GONG Big Bear station is exhibiting an unusually large number of camera resets. Each reset interrupts normal observing sequence, and impact the continuity of observations. This happen after recent unplanned power outage.  Engineering team is developing a mitigation approach to resolve the issue.

Flares, filament eruptions, but no CME?

Major (M- and X-class) flares and filament eruptions are usually accompany CMEs, but not always. On 31 August 2025 at about 14:00 UT, M1.3-class flare was recorded in NOAA active regions 14197. This is the region that had about hundred sunspots early this week. The flare activated large quiescent filament south of this region with a partial filament eruption at about 16:15 UT  (upper panel). Then, at about 18:00 UT a small two-ribbon flare and filament eruption were observed in NOAA region 14202 to the East of region 14197 (second panel from the top). See GONG video of these events at the bottom panel.  Despite this activity, there was no obvious sign of CMEs in LASCO coronagraph. There is gap in observations in LASCO C2 between 17:24 UT and 18:36 UT, and coronal streamers appear to be pushed apart during this gap. So, maybe it was a CME but LASCO missed it? Or maybe these were the  failed filament eruptions?