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.