Solar Storm Threat Analysis - Impact
Solar Storm Threat Analysis - Impact
Solar Storm Threat Analysis - Impact
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
<strong>Impact</strong>, 2007 James A. Marusek<br />
objects and dissipate significant energy at a penetrated depth (referred to as Bragg peak). When the particles are<br />
slowed down at their penetrated depth (for 148 MeV protons, the Bragg peak is at approximately 140 mm [5.5<br />
inches]), the interaction time becomes larger and the value of the energy transfer is at its maximum. Now consider<br />
the above graph as a living organism. Water is a basic chemical component in humans. At the Bragg peak, a large<br />
amount of high-energy electrons are produced that cause multiple ionization events at the end of their range in a<br />
distance that corresponds to the cross section of a deoxyribonucleic acid (DNA) molecule. This ionization produces<br />
cluster damage at the DNA level. Energetic protons, neutrons and ions have a greater biological efficiency than Xrays<br />
and Gamma Rays to induce genetic damage. X-rays can produce isolated single and double DNA strand breaks,<br />
which can be repaired by the cells rather quickly and cleanly. High-energy proton and ion radiation produces<br />
complex cluster damage to the DNA strands that are significantly less repairable. A macroscopic tumor may<br />
originate from only one transformed cell. If a single mutated cell survives, cancer may develop.<br />
Figure 4. Proton, ion and photon radiation penetration through water. 26<br />
Sudden Cardiac Death (SCD, commonly referred to as cardiac arrest) is death of a cardiac origin occurring within 1<br />
hour of preliminary symptoms. In general, this is caused by cardiac arrhythmias, electrical heart instability and<br />
heart rhythm disturbances. A study by Stoupel et al. of 788 SCDs over a 36 month period in the Baku capital city of<br />
Azerbaijan showed a correlation between SCDs and solar storms. 27 They found that days producing SCDs had an<br />
average of 8,538 imp/min daily neutron activity, compared to the daily average of 8,475 imp/min. When they<br />
looked at the days with the greatest number of SCDs (4-5), the neutron count on those days jumped even higher to<br />
8,657 imp/min. High-energy neutrons are created from the collision of high energy protons and ions with the<br />
Earth’s atmosphere. In general, they are primarily created by GCRs. But very energetic SPEs will also produce<br />
high-energy neutrons. Therefore neutron activity can be viewed as function of both GCRs combined with very<br />
high-energy solar cosmic rays. There is another aspect of this study that is also interesting. Refer to Table 6.<br />
During quiet days, SCDs are solely influenced by Galactic Cosmic Rays (GCRs). But as weak solar storms pass<br />
near the planet, SCD rates tend to drop. CMEs even mild ones contain strong magnetic fields that can efficiently<br />
deflect incoming GCRs, shielding Earth from their effect. This phenomenon is known as the “Forbush decrease”.<br />
Then as the intensity of the solar storm increases further, the quantity of the SPE high-energy particles increase, and<br />
they become a dominant factor in sudden death morbidity rates. A small number of these SPE nuclear particles are<br />
able to penetrate the Earth’s magnetic field and atmosphere and reach the planet’s surface. The intense ionization<br />
that occurs when one of these particles enters the human body and thermalizes is sufficient to produce an electrical<br />
pulse that short circuits the heart rhythm.<br />
Table 6. Sudden Cardiac Death Compared to Geomagnetic Activity 27<br />
Geomagnetic Activity<br />
Category<br />
SCD Distribution<br />
Quiet (I°) 0.78<br />
Unsettled (II°) 0.66<br />
Active (III°) 0.64<br />
Minor Geomagnetic <strong>Storm</strong> (IV°) 0.92<br />
19