Post on 17-Jan-2016
Toward a complete measurement Toward a complete measurement of the thermodynamic state of an of the thermodynamic state of an
impact-induced vapor cloudimpact-induced vapor cloud
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.
TemperatureTemperature TTPressure Pressure PPDensityDensity EntropyEntropy ssChemical compositionChemical composition xxIonization ratioIonization ratio
}Two of these four
The thermodynamic state of an impact vapor cloud was difficult.
Very high velocity launchers (>5km/s)
Ultra-high speed detector (~10-6 seconds)
Diagnostic tools for temperature, pressure,
and chemical composition
The thermodynamic state of an impact vapor cloud was difficult.
Not many facilities can achieve this velocity.
Ultra-high speed detector (~10-6 seconds)
Diagnostic tools for temperature, pressure,
and chemical composition
The thermodynamic state of an impact vapor cloud was difficult.
Not many facilities can achieve this velocity.
Regular CCD is too slow (~10-3 seconds).
Diagnostic tools for temperature, pressure,
and chemical composition
The thermodynamic state of an impact vapor cloud was difficult.
Not many facilities can achieve this velocity.
Regular CCD is too slow (~10-3 seconds).
Regular thermometers, barometers, and
chromatographs cannot be used.
The thermodynamic state of an impact vapor cloud was difficult.
Not many facilities can achieve this velocity.
Regular CCD is too slow (~10-3 seconds).
Regular thermometers, barometers, and
chromatographs cannot be used.
High-speed spectroscopyHigh-speed spectroscopy High-speed spectroscopyHigh-speed spectroscopy
Impact Flash SpectroscopyImpact Flash SpectroscopyImpact Flash SpectroscopyImpact Flash Spectroscopy
0
500
1000
1500
2000
2500
3000
3500
450 500 550 600 650
Inte
nsi
ty (
a.u
.)
Wavelength (nm)
3600K Blackbody
Quartz into Dolomite
CaOCaO
Ca
5.22km/s 60° 0-20µs
CaCaCaCaCa Mg NaCa Ca Ca
MgO
Pretty complex!
Impact Flash SpectroscopyImpact Flash SpectroscopyImpact Flash SpectroscopyImpact Flash Spectroscopy
0
500
1000
1500
2000
450 500 550 600 650
Inte
ns
ity
(a
.u.)
Wavelength (nm)
CaCa CaCaCaCa CaCa CaCaCaMg Na
CaO CaO
Ca
58.3
Quartz impact into Dolomite Block
60°, 5.27km/s, 0 - 2 µs
56.659.360.960.963.2 45.424.458.655.660.154.3 51.6
45.4
Ca
60.7+
52.6
Energy level (1000K)
High speed and high resolution are required.
Impact Flash SpectroscopyImpact Flash SpectroscopyImpact Flash SpectroscopyImpact Flash Spectroscopy
0
1000
2000
3000
4000
450 500 550 600 650
Inte
ns
ity
(a
.u.)
Wavelength (nm)
CuCuCuCu Ca Ca Ca Ca CaCaCaCa Na
Mg
Ca
CaOCaO
Ca CuCa76.0
Ca
44.3
Cu44.389.8 71.8 43.9
Copper impact into Dolomite Block
30°, 5.33km/s, 0 - 2µs
Energy level (1000K)
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.