POTENTIAL PLAGE AREA
Sunspots have been used as a marker for Solar activity for hundreds of years, but in reality they are just that. A sunspot is a cooler area on the Sun that is affected by localized increased magnetic fields, but surrounding that cooler area is a brighter/warmer area that is seen more easily from side on (as the area approaches and leaves the visible disk) and is nearly invisible when viewed straight on. These areas known as Plage can exist without sunspots and are thought to be the source of increased UV production, F10.7 flux, TSI (total solar irradiance) and to some extent towards the solar wind.
During the current sunspot area of 1040 we have witnessed for the first time during SC24 a return of a previous active region that began life as 1035 and has been active for a full solar revolution. These regions are common once the cycle gets underway but perhaps during this cycle they will be less common. Both 1035 and 1040 displayed very similar spot size and configuration along with the overall growth pattern, but the underlying magnetic fields are vastly different. Both areas recorded quite different results when comparing F10.7 flux, the expected TSI and UV results should follow suit. The solar wind values are also very different but there is also coronal hole contribution that needs to be taken into account. To gain further knowledge on the Plage area the Layman's Count will implement a new method called the Potential Plage Area (PPA) which will measure the underlying magnetic area and subtract the darker colder sunspot area.
To achieve this the method is as follows:
1. Use the SOHO Magnetogram 1024 x 1024 images to calculate the brighter and darker areas that are a result of higher magnetic activity. A threshold test will be performed on each pixel, a greyscale reading of 0-75 and 180-255 will isolate pixels involved with high activity and give us an overall magnetic region size in pixels. This will be performed on the entire solar disk at the height of individual sunspot activity (highest pixel count via the Layman's Count).
2. Deduct the Layman's pixel count from the magnetic area count, leaving the Potential Plage Area.
Sunspot 1035 achieved a Layman's Count of 732 pixels and a PPA of 2040 pixels.
Sunspot 1040(still measuring) had a comparison Layman's Count of 801 pixels and a PPA of 3257 pixels.
There is a clear difference in potential showing 1040 to have a magnetic area around 60% bigger than 1035 when viewing the whole disk. This method should also be useful during times of multiple occurring sunspots. Watch for updates and a monthly graph on the Layman's Sunspot page.