Toward a complete Toward a complete measurement of the measurement of the thermodynamic state of thermodynamic state of an impact-induced vapor an impact-induced vapor cloud cloud S. Sugita, K. Hamano, T. S. Sugita, K. Hamano, T. Matsui Matsui University of Tokyo University of Tokyo T. Kadono T. Kadono Institute for Earth’s Evolution Institute for Earth’s Evolution (IFREE) (IFREE) P. H. Schultz P. H. Schultz
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Toward a complete measurement of the thermodynamic state of an impact-induced vapor cloud S. Sugita, K. Hamano, T. Matsui University of Tokyo T. Kadono.
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Toward a complete measurement Toward a complete measurement of the thermodynamic state of an of the thermodynamic state of an
S. Sugita, K. Hamano, T. MatsuiS. Sugita, K. Hamano, T. MatsuiUniversity of TokyoUniversity of Tokyo
T. KadonoT. KadonoInstitute for Earth’s Evolution (IFREE)Institute for Earth’s Evolution (IFREE)
P. H. SchultzP. H. SchultzBrown UniversityBrown University
Importance of impact vaporizationImportance of impact vaporization
Impact degassing (e.g., K/T)Impact degassing (e.g., K/T) Accretion of an atmosphereAccretion of an atmosphere Atmospheric erosion (e.g., Mars)Atmospheric erosion (e.g., Mars)
However, physical state (e.g., EOS) However, physical state (e.g., EOS) and chemical reaction rates are and chemical reaction rates are highly uncertain.highly uncertain.
The key is the The key is the thermodynamic statethermodynamic state of resulting impact vapor clouds.of resulting impact vapor clouds.
The key is the The key is the thermodynamic statethermodynamic state of resulting impact vapor clouds.of resulting impact vapor clouds.
Photonic emission from an atomPhotonic emission from an atomPhotonic emission from an atomPhotonic emission from an atom
Photonic emission from an atomPhotonic emission from an atomPhotonic emission from an atomPhotonic emission from an atom
Photonic emission from an atomPhotonic emission from an atomPhotonic emission from an atomPhotonic emission from an atom
Il ,m
hlm
4A
l,mgmNexp
Em
kT/ Z (T)( )
where h, v, A, gh, v, A, g are constant; Z(T)~Z(T)~11.
ln ˆ I l ,m
Em
kT ln N
Emission intensity depends on both temperature and chemical composition.
where ˆ I l ,m
I
l ,m
Al,m
gmhlm
4
Boltzmann DiagramBoltzmann Diagram
5
10
15
20
0 20,000 40,000 60,000 80,000 100,000
ln (
In
m/4
An
mg
nh n
m)
En/k (K)
Copper Emission
Calcium Emission
Number of Ground-Level Copper Atoms
Number of Ground-Level Calcium Atoms
Temperature Temperature TT Chemical composition Chemical composition xx Ionization ratio Ionization ratio
Thermodynamic stateThermodynamic state of impact vapor of impact vaporThermodynamic stateThermodynamic state of impact vapor of impact vapor
TemperatureTemperature T T Pressure Pressure PPDensityDensity EntropyEntropy ssChemical compositionChemical composition x x Ionization ratioIonization ratio
}Two of these four
Still not enough. We need one more!Still not enough. We need one more!
Line width measurementLine width measurement
Spectral line width is controlled by:Spectral line width is controlled by: Doppler broadeningDoppler broadening
Stark (Lorentz) broadening for HStark (Lorentz) broadening for H (Grie (Griem, 1964)m, 1964)
c
2kT
6.3x1016
ne2 / 3
(nm)
Gypsum vapor in argonGypsum vapor in argon
0
5
10
15
20
400 450 500 550 600 650 700
Inte
nsi
ty (
a.u
.)
Wavelength (nm)
H HH
Ar
100 - 200 ns
Laser simulation: Nd:YAG, 10ns, 6x1011W/cm2
Gypsum vapor in argonGypsum vapor in argon
0
5
10
15
400 450 500 550 600 650 700
Inte
nsi
ty (
a.u
.)
Wavelength (nm)
Ca Ca
H
Ca Ca
HH
400 - 500 ns
Laser simulation: Nd:YAG, 10ns, 6x1011W/cm2
Gypsum vapor in argonGypsum vapor in argon
0
5
10
15
20
25
30
400 450 500 550 600 650 700
Inte
nsi
ty (
a.u
.)
Wavelength (nm)
Ca Ca Ca Ca Ca CaNa
H
Ca
CaOCaO
H
4000 - 5000 ns
Laser simulation: Nd:YAG, 10ns, 6x1011W/cm2
Line width to pressureLine width to pressure
ne = 6.3 x 10221.5 (m-3)
= ne /NA (= 1 is assumed.)
P = RT
■ Saha’s equation or ion line intensity measurement should be used for an accurate estimate.
P-T diagramP-T diagram
0.01
0.1
1
8000 10000
Pre
ssu
re (
bar
)
Temperature (K)
20000
Slope: = 1.3
Thermodynamic state Thermodynamic state of gypsum vaporof gypsum vapor
Enthalpy (H) and Gibbs free energy (G) can be also obtained.
TemperatureTemperature T T = 12,000 K Pressure Pressure P P = 0.1 bar DensityDensity =1.7x10-3 kg/m3 EntropyEntropy s s = 10.5 kJ/K/kg
ConclusionConclusion
Although still model dependent, Although still model dependent,
we now have a method to measure we now have a method to measure
the thermodynamic state of an the thermodynamic state of an
impact-induced vapor cloud as a impact-induced vapor cloud as a
function of time and space.function of time and space.