Predictions of Intense Solar Activity Needed

Abstract

Many of the sophisticated modeling efforts of the Sun-to-Earth system currently underway do not address some very important impacts of the Sun on terrestrial technologies. Thus, there is a serious need for more detailed models and improved predictions of intense solar activity. This gap in current capabilities of predicting the intensity of solar activity–especially the intensities of solar X-ray and radio bursts–was spectacularly illustrated in December 2006 during the passage of solar active region 0930 across the Sun. The solar radio burst at about 1900 UT on 6 December lasted for more than an hour, is reported to have been one of the largest (if not the largest) bursts ever recorded at gigahertz frequencies, and caused havoc for GPS measurements on Earth. Accompanying the solar burst was one of the largest increases in solar electron fluxes observed at the L1 ACE spacecraft in the past decade or more. If the active region at the time of the solar burst was more centered in the direction of the Earth, a coronal mass ejection with a resulting huge magnetic disturbance with resulting technology impacts might have been expected at Earth. As it was, the technologies largely affected were GPS receivers and other receiving systems such as radars oriented slightly towards the Sun (including possibly some cellular phone cell sites, a situation still under investigation by researchers). None of these effects are addressed by most current modeling of the Sun-Earth system. Just because the effects from this event were limited to certain technologies and did not generate a large magnetic storm (which is what most space weather modeling is currently directed toward) does not make this solar event less important for space weather researchers, modelers, and system operators. Rather, it clearly points out that considerably more research and understanding are needed to predict the types of solar activity that can produce so unexpectedly the intense electromagnetic emissions observed on 6 December. Like large magnetic storms, we now know first hand that these types of events can also affect important navigation and communications technologies at essentially the same moment (just the light travel time) when the solar event is first observed at Earth. Louis J. Lanzerotti is editor of Space Weather, a distinguished research professor at the New Jersey Institute of Technology, and a consultant at Alcatel-Lucent Technologies’ Bell Laboratories.