CAPE CANAVERAL, Florida – NASA’s Solar Dynamic Observatory detected a giant hole in the Sun that produced a coronal high-speed stream which is forecast to hit Earth on March 24, 2023, along with solar winds striking the Earth’s atmosphere at 600 kilometers per second.
NOAA’s Space Weather Prediction Center has issued a G2 (Moderate) geomagnetic storm watch in effect for March 24, 2023, due to the effects of the coronal hole high speed stream (CH HSS).
This event is expected to bring a co-rotating interaction region (CIR) to Earth by March 24, followed by the onset of the CH HSS.
A CIR is the result of the interaction between a coronal hole high-speed stream and the relatively slower ambient solar wind speed. This interaction creates a compression region ahead of the HSS, which is anticipated to result in expected enhancements and disturbances in the solar wind field.
These combined CIR and CH HSS influences are likely to result in isolated periods of G2 storm levels on March 24. Solar wind speeds are expected to be in excess of 600 km/s and continue into 25 March.
According to the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center (SWPC), the storm watch means that the likelihood of a G2 storm occurring is increasing. A G2 storm can cause voltage control problems in power systems, high-latitude power systems may experience voltage alarms, and low-frequency radio navigation problems may occur.
Additionally, satellite operations may experience surface charging, increased drag, and orientation problems. Other possible impacts include intermittent satellite navigation and low-frequency radio navigation problems.
The SWPC advises power grid operators and satellite operators to take the necessary precautions to protect their systems during this event.
The SWPC is a part of the National Weather Service and provides real-time monitoring and forecasting of space weather events that can impact technological systems and infrastructure on Earth.
They work closely with other government agencies, the private sector, and international organizations to provide timely and accurate information to ensure the safety and reliability of critical infrastructure.
In extreme ultraviolet (EUV) and soft x-ray solar images, coronal holes appear as dark areas in the solar corona.
The reason for their darkness is that these regions are cooler, less dense, and consist of open, unipolar magnetic fields.
This unique magnetic field structure allows for the easy escape of the solar wind into space, resulting in streams of relatively fast solar wind, often referred to as high-speed streams when analyzing structures in interplanetary space.
Although coronal holes can develop at any time and location on the Sun, they are more prevalent and persistent during the years around solar minimum. The more persistent coronal holes can even last through several solar rotations (27-day periods). While coronal holes are most common and stable at the solar north and south poles, they can also expand to lower solar latitudes or develop in isolation from the polar holes.
As high-speed streams from persistent coronal holes interact with the slower ambient solar wind, a compression region forms, called a co-rotating interaction region (CIR). From the perspective of a fixed observer in interplanetary space, the CIR will lead the coronal hole high-speed stream (CH HSS). These persistent coronal holes serve as long-lasting sources for high-speed solar wind streams, resulting in isolated periods of G2 storm levels on Earth, as is currently anticipated for March 24th, 2023.