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| ||<-6> Conditions in Local Cloud, 3e5 H/m^3^, 5e-22 kg/m^3^ as perceived from moving frame|| | ||<-7>'''Conditions in Local Cloud, 3e5 H/m^3^, 5e-22 kg/m^3^ as perceived from moving frame'''|| |
Star Travel and the Interstellar Medium, particle effects
The interstellar medium - the coronal gas - forms a column between locations in space. The sun is 4 light years from one edge of a 60 light-year-across cloud with a density of 0.3 hydrogens per cubic centimeter, or 3e5 H/m3, encountering the sun as it moves towards Scorpio at 25 km/s. Around that cloud is the Local Bubble, 300 LY across with a density of 50 H/m3. A light year is 9.5e15 meters, so for the first 4 light years in one direction, and more than 50 LY in the opposite direction, we encounter a column of hydrogen atoms with a density of about 1e21 H/m2-LY. That is the density of a layer of liquid water 30 nm thick per light year. 100 light years, 3 micrometers.
These protons will implant themselves in the surface of any object passing through them. At a mere 25 km/s, the energy per proton is 3.6 electron volts - many will bounce off. Approaching the speed of light, the energy approaches multiples of the mass energy of the proton, 938 MeV/c2. That will damage solid structure to the implant depth.
I don't know how much. A particle physicist can tell you how deep.
Conditions in Local Cloud, 3e5 H/m3, 5e-22 kg/m3 as perceived from moving frame |
||||||
speed |
v/c |
1\over{c^2-v^2} |
energy |
flux |
Pressure |
|
m/s |
|
|
|
1/m2-s |
Pascals |
|
25k |
8e-5 |
1 |
4 eV |
8e9 |
|
|
30k |
1e-4 |
1 |
5 eV |
9e9 |
|
|
100k |
3.3e-4 |
1 |
50 eV |
3e10 |
|
|
300k |
1e-3 |
1 |
500 eV |
9e10 |
14μ |
|
1M |
3.3e-3 |
1 |
5 keV |
3e11 |
500μ |
|
1.4M |
5e-3 |
1 |
10 keV |
4e11 |
1.4m |
low energy ion implantation |
3M |
1e-2 |
1 |
50 keV |
9e11 |
14m |
low energy van Allen belt |
4.2M |
1.4e-2 |
1 |
100 keV |
1.3e12 |
37m |
6000x more flux than 100 keV van Allen belt |
10M |
3.3e-2 |
1 |
500 keV |
3e12 |
0.5 |
high energy ion implantation |
14M |
4.2e-2 |
1 |
1 MeV |
4e12 |
1.4 |
2e5 more flux than 10 MeV van Allen belt |
30M |
0.10 |
1.01 |
5 MeV |
9e12 |
14 |
7 W/m2 particle power |
100M |
0.33 |
1.13 |
50 MeV |
3e13 |
570 |
|
200M |
0.67 |
1.80 |
380 MeV |
8e13 |
7K |
highest energy van Allen belt, 1e12 more flux |
250M |
0.83 |
3.28 |
500 MeV |
1.4e14 |
26K |
11 KW/m2 particle power |
