September '09

Propagation Forecast
At this time, the sun has been blank of official sunspots for over 41 days (www.solarcycle24.com)
The calm Solar Terrestrial conditions are likely to continue for the foreseeable future. According to the NOAA 27 day forecast, the Solar Flux will remain at 68 and the Boulder A index will remain mostly at 5, apart from some minor fluctuations between 2-6 September . The Boulder K Index will remain at 2 except on 2nd and 5th September, which should be only a minor variation of not more than 1 point, so Solar Cycle 24 is not making its presence known so far.
(From: http://www.wm7d.net/hamradio/solar/27d_forecast.shtml )

Solar cycle 24 Predictions.
The progressive Sunspot Number prediction chart on the Solar Cycle 24 website appears to be the most accurate long term forecast predicting the next peak to be in 2013: http://www.solarcycle24.com/sunspots.htm
This prediction has recently been amended: “Radio and Space Services has made a significant change to its forecast for solar cycle 24. The forecast cycle maximum smoothed sunspot number has been dropped from 134 to approximately 90. In addition the time of maximum has been shifted away by one year to September/October 2013. These changes were made due to the protracted solar minimum currently being experienced and the apparent statistical relationship between long solar minimums and lower following solar cycle’s maxima”. (Andy Sennit, Media Network 31 July 2009 via Mike Terry)
See also the Space Weather Prediction Centre: http://www.swpc.noaa.gov/

Optimum Working Frequency Charts. The Western Europe charts can be viewed at: http://hfradio.org/fot_7.html where you can cross reference the time and frequency with the path and it gives you a percentage. These should be accurate for 80% of the month depending on conditions. Links to other regions are included.

Predicting Space Weather (NASA Article: The Key to Understanding The Sun) “A better understanding of the Sun's magnetic field and its behaviour will allow us to make better predictions of space weather. Observations of magnetic fields associated with solar flares show that flares are likely to occur when the magnetic field lines linking two sunspots become sheared or twisted. Observations of the Sun's magnetic field over the last 20 years illustrates its behaviour over two sunspot cycles. However, predicting long-range behaviour, such as the size of the sunspot cycle, is still based on observing trends and patterns. We hope that in the near future we will understand the Sun well enough to make these predictions based on current conditions and past history using a mathematical model of the actual processes.”

Solar Magnetic Fields. “Magnetism is the key to understanding the Sun. Magnetism, or magnetic field, is produced on the Sun by the flow of electrically charged ions and electrons. Sunspots are places where very intense magnetic lines of force break through the Sun's surface. The sunspot cycle results from the recycling of magnetic fields by the flow of material in the interior. The prominences seen floating above the surface of the Sun are supported, and threaded through, with magnetic fields. The streamers and loops seen in the corona are shaped by magnetic fields. Magnetic fields are at the root of virtually all of the features we see on and above the Sun. Without magnetic fields the Sun would be a rather boring star”.

Measuring Magnetic Fields. “Magnetic forces change the direction of motion of moving charged particles like electrons. Because of this, electrons that orbit around a nucleus in one direction will have more energy than electrons that orbit about the nucleus in the opposite direction. This allows us to remotely measure the Sun's magnetic field by observing the difference in the energy of the light emitted as these electrons jump from orbit to orbit. With the proper instrumentation we can determine both the strength and the direction of the magnetic field all across the surface of the Sun.” ”. (More on this subject at: http://solarscience.msfc.nasa.gov/the_key.shtml )

Thanks also to Ken Fletcher and Mike Terry. Links can be found at http://www.jameswelsh.org.uk