page 7, lines 175/176:
"Cosmic radiation is composed of high-energy particles originating from space and from the Sun." As solar cosmic rays are not continuously present I propose:
"Cosmic radiation is composed of high-energy particles originating from space and occasionally from the Sun."
page 7, lines 177/178:
"Solar eruptions can also affect dose rate of cosmic radiation.": It is not the solar eruption that affects the dose rate but the solar cosmic rays which are produced in high-energy processes at or near the Sun in connection with solar flares. A possible formulation:
"In connection to solar flares energetic solar cosmic ray particles can be produced which may increase the radiation exposure at flight altitudes and high geomagnetic latitudes for a short time."
page 10, lines 321-323 "Occasional flyer":
I would desire a more quantitative definition for "occasional flyer" than only "from time to time".
page 12, lines 371-373 "Solar particle event or solar proton event (SPE)":
Instead of the given definition, I propose something like:
"A fluence of energetic particles (mostly protons) that are emitted from the Sun and are accelerated either close to the Sun during the solar flare or in the interplanetary space by CME shock(s)."
page 12, lines 374-380 "Sun’s solar wind":
"Sun's solar" is a pleonasm. I would either write: "Sun's stellar wind" or more common simply "Solar wind".
Definition of "Solar wind", proposal:
"The solar wind is a stream of charged particles (mostly electrons, protons and alpha particles) released from the upper atmosphere of the Sun (corona) with typical speeds ~400 km/s (slow solar wind) and ~500-800 km/s (fast solar wind). Embedded in the solar-wind plasma is the interplanetary magnetic field which affects the flux of galactic cosmic radiation entering into the inner heliosphere. The solar wind characteristics varies with the 11-year solar activity and in turn the galactic cosmic ray intensity in the heliosphere. Galactic cosmic ray flux is maximal when the solar activity is at its minimum and vice versa."
In the context of the present document I would not mention the aurora.
page 15, line 455:
Instead of "solar eruption" the expression "solar flare" is usually used in the English language.
page 15, line 456:
The failure of the telegraph systems occured not immediatly after the observation of the solar flare, as the reason for the failures in the telegraph systems were not the solar cosmic ray flux but the storm in the geomagnetic field which was caused by the passage of a shock wave over the Earth. Therefore I propose to change the sentence:
"Telegraph systems failed all over Europe and America, and auroras filled the sky as far south as the Caribbean."
to something like:
"About 18 hours after the observation of the solar flare, a shock wave driven by a coronal mass ejection passed the Earth which caused a geomagnetic storm and in turn telegraph systems failed all over Europe and America, and auroras filled the sky as far south as the Caribbean."
I think the following sentence starting with "Today, it is known ..." must then be adapted accordingly.
page 15, line 482/483:
"The Earth is exposed continuously ... – galactic cosmic radiation (GCR) – and from the Sun – solar cosmic radiation (SCR)." --->
"The Earth is exposed continuously ... – galactic cosmic radiation (GCR) – and occasionally from the Sun – solar cosmic radiation (SCR)."
Then the sentence: "In addition, the Earth is exposed occasionally to bursts of energetic particles from the Sun (SPEs)." can be deleted.
page 16, Figure caption to Fig. 2:
Proposal:
"The anti-correlation between the activity of the Sun (expressed as the monthly smoothed sunspot number – blue curve) and the cosmic radiation exposure (expressed as the monthly average count rates of the neutron monitor station Kerguelen – black curve) from 1964 to 2014 (Paris-Meudon Observatory data)."
page 17, line 532:
"... the electrons/positrons and neutrons are the larger components in dose ..." --->
"... the electrons/positrons and neutrons are the main components in dose ..."
page 18, line 561:
"According to Lantos and Fuller (2003), 64 SPEs were observed from 1942, and only 18 of them were associated with a significant likelihood of an increase ...": Lantos and Fuller says in the paper that 64 GLEs were observed from 1942 until August 2002. The number of SPEs in this time period is a multiple of 64. I propose to change this sentence as follows:
"According to Lantos and Fuller (2003), 64 GLEs were observed from 1942 until August 2002, and only 18 of them were associated with a significant likelihood of an increase ..."
In the text GLE is not yet defined. GLE stands for Ground Level Event or Ground Level Enhancement. SPE is a GLE when the solar cosmic ray event can be observed by grond based cosmic ray detectors as neutron monitors. It may be accepted that a significant increase in radiation dose rates at flight altitudes is only possible when a GLE is observed.
page 18, line 563:
The large SPE in April 1989, shown in Figure 4, was not observed at ground, i.e. no GLE. Therefore no additional radiation dose rate at flight altitudes is expected. Therefore "(like the SPE in April 1989)" can be deleted or should be changed to an other SPE which was also a GLE, e.g. "(like the GLE on 13 December 2006)" (= last large GLE).
page 33, line 1068/1069:
"The Earth is continuously bombarded from particles coming from deep space and the Sun." --->
"The Earth is bombarded from particles coming continuously from deep space and occasionally from the Sun."