Estimating the frequency of extremely energetic solar events, based on solar, stellar, lunar, and terrestrial records

By C. Schrijver, J. Beer, U. Baltensperger, E. Cliver, M. Gudel, H. Hudson, K. Mccracken, R. Osten, T. Peter, D. Soderblom and 2 more. 2012

138 citations recorded by the source corpus.

[1] The most powerful explosions on the Sun – in the form of bright flares, intense storms of solar energetic particles (SEPs), and fast coronal mass ejections (CMEs) – drive the most severe space-weather storms. Proxy records of flare energies based on SEPs in principle may offer the longest time base to study infrequent large events. We conclude that one suggested proxy, nitrate concentrations in polar ice cores, does not map reliably to SEP events. Concentrations of select radionuclides measured in natural archives may prove useful in extending the time interval of direct observations up to ten millennia, but as their calibration to solar flare fluences depends on multiple poorly known properties and processes, these proxies cannot presently be used to help determine the flare energy frequency distribution. Being thus limited to the use of direct flare observations, we evaluate the probabilities of large-energy solar events by combining solar flare observations with an ensemble of stellar flare observations. We conclude that solar flare energies form a relatively smooth distribution from small events to large flares, while flares on magnetically active, young Sun-like stars have energies and frequencies markedly in excess of strong solar flares, even after an empirical scaling with the mean coronal activity level of these stars. In order to empirically quantify the frequency of uncommonly large solar flares extensive surveys of stars of near-solar age need to be obtained, such as is feasible with the Kepler satellite. Because the likelihood of flares larger than approximately X30 remains empirically unconstrained, we present indirect arguments, based on records of sunspots and on statistical arguments, that solar flares in the past four centuries have likely not substantially exceeded the level of the largest flares observed in the space era, and that there is at most about a 10% chance of a flare larger than about X30 in the next 30 years.

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Citations in the corpus

The 1859 space weather event revisited: limits of extreme activity (2013, background): “Schrijver et al. (2012) suggested a maximum radiative energy release of ~10 33 ergs while Aulanier et al. (2013) obtained a peak flare energy of ~6 x 10 33 ergs from a 3D MHD simulation for eruptive flares.”
The standard flare model in three dimensions II: upper limit on solar flare energy (2012, methodology): “…(2008), who reported that the size of sunspot groups follows a clear log-normal distribution up to 3000 MSH, and to Cliver & Svalgaard (2004) and Schrijver et al. (2012), who argue that this upper limit on flare energy was never reached in any observed solar flare since, even including the…”
KEPLER FLARES. I. ACTIVE AND INACTIVE M DWARFS (2014, background): “…considerable interest in the solar literature concerning the value of α, since a flare energy distribution with α > 2 extending to low flare energies would potentially provide enough energy from flares to heat the solar corona (Parker 1988; Hudson 1991; Hannah et al. 2011; Schrijver et al. 2012).”
SUPERFLARES ON SOLAR-TYPE STARS OBSERVED WITH KEPLER. I. STATISTICAL PROPERTIES OF SUPERFLARES (2013, background): “Furthermore, we show the frequency of stellar flares on κ Cet with a thick dotted line in Figure 10. κ Cet is a G5-type main sequence star (Teff = 5520 K, v sin i = 3.9 km s−1, Prot = 9.4 days; Schrijver et al. 2012; Audard et al. 2000), and hence is slightly cooler than Sun-like stars.”
The AD775 cosmic event revisited: the Sun is to blame (2013, background): “This is corroborated by the steep tail of the SEP event fluence distribution (Schrijver et al. 2012).”
The Two Sources of Solar Energetic Particles (2012, methodology): “Under thes circumstances we must be content with the more limited statistics of recent SEP studies (e.g. Reedy 1996, 2006, 2012; Schrijver et al. 2012).”
25 Years of Self-Organized Criticality: Solar and Astrophysics (2014, background): “…tracers (nitrate concentrations in polar ice cores or select radionuclides) extend over millenia, but are not reliable proxy records of solar flares or SEP events (Schrijver et al. 2012), because nitrate spikes in ice cores can also be caused by biomass burning plumes (Wolff et al. 2012).”
MAGNETIC PROPERTIES OF SOLAR ACTIVE REGIONS THAT GOVERN LARGE SOLAR FLARES AND ERUPTIONS (2016, background): “Therefore, only parts of the sunspots might be involved in the flare reconnection process (see also Schrijver et al. 2012).”
THE KEPLER CATALOG OF STELLAR FLARES (2016, background): “In the the case of the Sun this power-law is traced over ∼8 orders of magnitude in observed flare energy (Schrijver et al. 2012; Maehara et al. 2015).”
Geomagnetic storms: historical perspective to modern view (2016, background): “This is because magnetic reconnection at the Sun is responsible for both phenomena at these intense levels (Shibata et al.”
Statistical properties of superflares on solar-type stars based on 1-min cadence data (2015, background): “These values are lower than the upper limits derived from radionuclides in lunar samples (Schrijver et al. 2012).”
Can Superflares Occur on Our Sun (2012, background): “Schrijver et al. (2012) also argued that flares with energy well above about 1033 erg are unlikely to occur, considering historical records of sunspot size over the recent 400 yr.”