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| 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/c^2^. That will damage solid structure to the implant depth. | 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/c^2^. That will damage solid structure to the implant depth. The table below (from Janni 1966) shows stopping range in silicon. |
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| I don't know how much. A particle physicist can tell you how deep. ||<-7>'''Conditions in Local Cloud, 3e5 H/m^3^, 5e-22 kg/m^3^ as perceived from moving frame'''|| || speed || v/c ||$1\over{c^2-v^2}$||energy||flux||Pressure|| || || m/s || || || ||1/m^2^-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/m^2^ 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/m^2^ particle power || |
||<-10>'''Conditions in Local Cloud, 3e5 H/m^3^, 5e-22 kg/m^3^ as perceived from moving frame'''|| || speed || v/c ||$1\over{c^2-v^2}$||energy||flux||<2>Stopping Range est mm||Pressure|| || || m/s || || || ||1/m^2^-s|| SiO2 || H2O || Pascals || || || 25k || 8e-5 || 1 || 4 eV || 8e9 || || || || || || 30k || 1e-4 || 1 || 5 eV || 9e9 || || || || || || 100k || 3.3e-4 || 1 || 50 eV || 3e10 ||1.1e-4||2.8e-4|| || || || 300k || 1e-3 || 1 || 500 eV || 9e10 ||3.3e-4||8.5e-4|| 14μ || || || 1M || 3.3e-3 || 1 || 5 keV || 3e11 ||1.6e-3||4.1e-3|| 500μ || || || 1.4M || 5e-3 || 1 || 10 keV || 4e11 ||2.5e-3||6.5e-3|| 1.4m || low energy ion implantation || || 3M || 1e-2 || 1 || 50 keV || 9e11 ||8.0e-3||2.1e-2|| 14m || low energy van Allen belt || || 4.2M || 0.014 || 1 || 100 keV || 1.3e12 ||1.5e-2|| 0.04 || 37m || 100 keV van Allen belt, 6000x more flux || || 10M || 0.033 || 1 || 500 keV || 3e12 || 0.06 || 0.16 || 0.5 || high energy ion implantation || || 14M || 0.042 || 1 || 1 MeV || 4e12 || 0.12 || 0.31 || 1.4 || 1 MeV van Allen belt, 2e5 more flux || || 30M || 0.10 || 1.01 || 5 MeV || 9e12 || 0.44 || 1.15 || 14 || 7 W/m^2^ particle power || || 100M || 0.33 || 1.13 || 50 MeV || 3e13 || 3.7 || 9.5 || 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/m^2^ particle power || |
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 Local 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. The table below (from Janni 1966) shows stopping range in silicon.
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 |
Expected "%" after "2", got "" Stopping Range est mm |
Pressure |
|
||
m/s |
|
|
|
1/m2-s |
H2O |
Pascals |
|
||
25k |
8e-5 |
1 |
4 eV |
8e9 |
|
|
|
|
|
30k |
1e-4 |
1 |
5 eV |
9e9 |
|
|
|
|
|
100k |
3.3e-4 |
1 |
50 eV |
3e10 |
1.1e-4 |
2.8e-4 |
|
|
|
300k |
1e-3 |
1 |
500 eV |
9e10 |
3.3e-4 |
8.5e-4 |
14μ |
|
|
1M |
3.3e-3 |
1 |
5 keV |
3e11 |
1.6e-3 |
4.1e-3 |
500μ |
|
|
1.4M |
5e-3 |
1 |
10 keV |
4e11 |
2.5e-3 |
6.5e-3 |
1.4m |
low energy ion implantation |
|
3M |
1e-2 |
1 |
50 keV |
9e11 |
8.0e-3 |
2.1e-2 |
14m |
low energy van Allen belt |
|
4.2M |
0.014 |
1 |
100 keV |
1.3e12 |
1.5e-2 |
0.04 |
37m |
100 keV van Allen belt, 6000x more flux |
|
10M |
0.033 |
1 |
500 keV |
3e12 |
0.06 |
0.16 |
0.5 |
high energy ion implantation |
|
14M |
0.042 |
1 |
1 MeV |
4e12 |
0.12 |
0.31 |
1.4 |
1 MeV van Allen belt, 2e5 more flux |
|
30M |
0.10 |
1.01 |
5 MeV |
9e12 |
0.44 |
1.15 |
14 |
7 W/m2 particle power |
|
100M |
0.33 |
1.13 |
50 MeV |
3e13 |
3.7 |
9.5 |
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 |
|
