Rosetta/SREM Solar Particle Event

Following the arrival of the Rosetta spacecraft at the comet  67/P Churyumov-Gerasimenko on 6 August, the first solar particle event to reach the spacecraft at the comet location has been observed by the on-board ESA Standard Radiation Environment Monitor (SREM). The diagram below shows the timeline of radiation counts between 1 September and 3 September as observed by three of the SREM energy channels TC3, S12 and TC2, sensitive to protons of energies above 12, 27 and 49 MeV respectively.

The solar event in question took place on 1 September and originated from the far side of the Sun, just beyond the northeastern limb, and hence was not visible at Earth. However it was seen by the NASA Stereo spacecraft based behind the Sun.The present location of the Rosetta and the comet 67/P is currently such that there is a good heliospheric magnetic connection between the Earth and Rosetta. This translates to good correlation of the observations between the SREM unit on Rosetta and another one on the Earth-orbiting INTEGRAL spacecraft, the counts for which are also shown for comparison in the second plot below.

Static plots of the SREM data are available, as well as via an experimental dynamic plotting tool and more information on this event are available from our SEP page.
Rosetta/SREM TC3, S12 and TC2 channel measurements during the 2014-09-02 solar particle event.
Rosetta/SREM TC3, S12 and TC2 channel measurements during the 2014-09-02 solar particle event.
Comparison of Rosetta/SREM and Integral/IREM TC3 channels during 2015/09/01 Solar Particle Event.
Comparison of Rosetta/SREM and Integral/IREM TC3 channels during 2015/09/01 Solar Particle Event.

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