Chronology of ‘killer’ electrons: Solar cycles 22 and 23

If the Sun is so quiet, why is the Earth ringing? A comparison of two solar minimum intervals

“…OMNI solar wind speed (indigo) is overlaid (a) with density (pink); (b) with combined NOAA‐DMSP auroral electron power [ Emery et al , 2008] (orange); and (c) with >2 MeV outer radiation belt electron flux (green) (GOES 8: 1 May 1995 to 31 May 2003; GOES 10: 1 January 2003 to 31 December 2003; GOES 12: 1 January 2004 to 31 October 2008). The GOES satellite data were calibrated prelaunch and intercalibrated in flight when pairs of spacecraft operated at the same longitude [see Wrenn , 2008, and references therein]. All data have undergone a 27‐day running average to highlight long‐term trends.…”

“…Figure 3c shows that the flux of electrons greater than 2 MeV at 6–7 Earth radii above the equator (green) dropped steeply toward solar minimum in 1996, and, in fact, nearly disappeared around summer solstice of that year [ Li et al , 2001] (one and a half months before WSM began). However, the decline in the descending phase of the current cycle was relatively slow [ Wrenn , 2008], and we show in Figure 3c that, even after sunspots and solar activity had dropped to levels lower than last minimum, radiation belt fluxes in the outer belt were still pumped up in association with continuing periodic HSS. For the months surrounding WHI, they were at levels on average 3.4 times higher (or 71% higher for a logarithmic comparison) than those surrounding WSM.…”

“BION-M” No. 1 spacecraft radiation environment as observed by the RD3-B3 radiometer-dosimeter in April–May 2013

“…1 spacecraft reached the "horns" of the ORB, the dose rates are enhanced by relativistic electrons trapped in the ORB. Relativistic electron enhancements in the ORB are one of the major manifestations of space weather (Zheng et al, 2006;Wrenn, 2009) near Earth's orbit. These enhancements occur mainly after magnetic storms.…”

“…The dose rate curve in the L $ 4 region corresponds to the flux maxima but with smaller amplitudes. These maximums have to be attributed to the crossings of the outer radiation belts regions where relativistic electron fluxes are observed (Zheng et al, 2006;Wrenn, 2009;Dachev et al, 2009Dachev et al, , 2012a. In the L $ 4 regions the RD3-R3 instrument registered bremsstrahlung radiation from the energetic electrons impacting the walls of the capsule but this source cannot be distinguished from the primary electron flux because both sources deliver similar small specific doses.…”

Introduction to Special Issue on high speed solar wind streams and geospace interactions (HSS–GI)

“…Lindsay et al, 1995;Borovsky and Denton, 2006) and whilst CME-events certainly produce the largest geomagnetic storms, HSS-events are particularly important for phenomena such as relativistic electron acceleration, radiation belt enhancements, and satellite anomalies (e.g. Wrenn et al, 2009). In terms of the energy input to the magnetosphere, HSSs are found to input a totalenergy-per-event which is similar in magnitude to that during CMEs; indeed the ratio of the energy-depositedin-the-magnetosphere to the energy-input-to-the-magnetosphere appears to be greater for HSSs than for CMEs (e.g.…”