# The Sun and Space Weather
## 7 Space Weather Events and Spacecraft Anomalies
Particle data in (**a**,**b**) are from IMP 8. The frequency of anomalies as a function of time elapsed since the onset of a proton event for high-altitude (**c**) and low-altitude (**d**) spacecraft, irrespective of inclination (adapted from [161]). The relativistic electrons noted above are part of the highly variable Earth's outer radiation belt. The inner belt is populated mainly by energetic protons resulting from the galactic cosmic rays via the CRAND (cosmic ray albedo neutron decay) mechanism (e.g., [167]. SEPs from energetic CMEs also contribute to the inner belt (see e.g., [168]). The CRAND mechanism can also contribute to energetic electrons in the inner belt [169]. Precipitation of radiation belt particles, SEPs, and GCRs to the Earth's polar atmosphere affects the atmospheric chemistry, including ozone depletion (see [170] and references therein). SEPs penetrate the polar atmosphere to various depths depending on their energy: 1, 10, 100, and 1000 MeV particles can penetrate to the mesopause, mesosphere, stratosphere, and troposphere, respectively. The 100 MeV particles in the stratosphere can dissociate molecules to produce radicals such as HOx and NOx that react with ozone, \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Particle Type** & **Energy Range** & **Effects** & **Sources** \\ \hline Electrons & 10–100 keV & \multicolumn{2}{c}{Spacecraft charging} & \multicolumn{1}{c}{Trapped particles} \\ Electrons & \textgreater{}100 keV & \multicolumn{2}{c}{Deep dielectric charging, solar} & \multicolumn{1}{c}{Trapped particles} \\ Electrons & \textgreater{}1 MeV & \multicolumn{2}{c}{cell damage} & \multicolumn{1}{c}{Trapped/quasi trapped} \\ Protons & 0.1–1 MeV & \multicolumn{2}{c}{Surface damage to materials} & \multicolumn{1}{c}{Trapped particles} \\ Protons & 1–10 MeV & \multicolumn{2}{c}{Displacement damage in} & \multicolumn{1}{c}{Trapped particles, ESP} \\  & & solar cells & & \\ Protons & \textgreater{}10 MeV & \multicolumn{2}{c}{Ionization, displacement} & \multicolumn{1}{c}{Radiation belt, SEPs,} \\  & & damage; sensor background & \multicolumn{1}{c}{GCRs} \\ Protons & \textgreater{}30 MeV & \multicolumn{2}{c}{Damage to biological systems} & \multicolumn{1}{c}{Radiation belt, SEPs,} \\  & & & GCRs \\ Protons & \textgreater{}50 MeV & \multicolumn{2}{c}{Single event effects} & \multicolumn{1}{c}{Radiation belt, SEPs,} \\  & & & GCRs \\ Ions & \textgreater{}10 MeV/nuc & \multicolumn{2}{c}{Single event effects} & \multicolumn{1}{c}{SEPs, GCRs} \\  & & Single event effects, hazard to & \multicolumn{1}{c}{} \\ Protons & \textgreater{}500 MeV & \multicolumn{2}{c}{humans in polar flights and in} & \multicolumn{1}{c}{SEPs, GCRs} \\  & & deep space & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Particles in various energy ranges, their sources, and their effects. Figure 18: (**left**) The frequency of spacecraft anomalies as a function of time elapsed since the storm sudden commencement (SSC) (from [161]). (**right**) The progressive increase in relativistic electron flux at various energies following a geomagnetic storm due to a high-intensity, long-duration continuous auroral electrojet activities (HILDCAA) event (from [165]). The initial dip in the electron flux is due to the compression of the magnetosphere by the HSS. contributing to ozone depletion [171]. The GeV particles reach the troposphere, where the primary particles produce air shower, including secondary particles such as muons and neutrons detected by ground-based monitors (see e.g., [172] for a review). GLEs have a harder spectrum than regular SEP events and SEP events associated with filament eruption CMEs [157]. GLEs deposit their energy in Earth's polar and mid-latitude regions. Because of their higher energy, GLEs also significantly impact solar cells and star-sensor pointing systems on spacecraft. They also increase of the radiation environment on spacecraft components and transpolar aircraft. Solar disturbances have a significant impact on terrestrial technological systems as well [173].