PROPERTIES OF THE PLANETARY MATERIALS He, SiO2, AND N2 AT DYNAMIC HIGH PRESSURES AND TEMPERATURES

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PROPERTIES OF THE PLANETARY MATERIALS He, SiO2, AND N2 AT DYNAMIC HIGH PRESSURES

AND TEMPERATURES

W. Nellis, N. Holmes, A. Mitchell, M. van Thiel, H. Radousky, D. Hamilton, S. Henning

To cite this version:

W. Nellis, N. Holmes, A. Mitchell, M. van Thiel, H. Radousky, et al.. PROPERTIES OF THE PLANETARY MATERIALS He, SiO2, AND N2 AT DYNAMIC HIGH PRESSURES AND TEMPERATURES. Journal de Physique Colloques, 1984, 45 (C8), pp.C8-105-C8-107.

�10.1051/jphyscol:1984820�. �jpa-00224318�

JOURNAL DE PHYSIQUE

Colloque C8, supplkrnent a u n O l I, Tome 45, novernbre 1984 page C8-105

PROPERTIES OF THE PLANETARY M A T E R I A L S He, S i O 2 . AND N 2 A T DYNAMIC H I G H PRESSURES AND TEMPERATURES

W.J. Nellis, N.C. Holmes, A.C. Mitchell, M. Van Thiel, H.B. Radousky, D.C. Hamilton and S. Henningr

U n i v e r s i t y o f C a Z i f o m i a , Lnwrence Livermore National Laboratorg, Livermore, CA 94550, U. S. A .

* ~ n i v e r ~ i t y o f Lund, Sweden

Resume - On a mesure en r e g i m e dynamique l e s p r o p r i e t e s p h y s i q u e s a h a u t e

I

p r e s s i o n e t h a u t e t e m p e r a t u r e de t r o i s m a t e r i a u x que l ' o n pense e t r e des c o n s t i t u a n t s des p l a n e t e s e x t e r n e s .

A b s t r a c t - P h y s i c a l p r o p e r t i e s have been measured dynamical l y a t r e 1 e v a n t h i g h p r e s s u r e s and t e m p e r a t u r e s f o r t h r e e m a t e r i a l s t h o u g h t t o c o n s t i t u t e t h e o u t e r p l a n e t s .

The f i r s t shock-compression d a t a f o r l i q u i d He were measured. U s i n g a

t w o - s t a g e l i g h t - g a s gun, l i q u i d He a t 4.3 K and 1 atm was shocked i n t h e r a n g e 1.2-16 GPa (12-160 k b a r ) and double-shocked t o 56 GPa. The e q u a t i o n - o f - s t a t e d a t a a r e i n good agreement w i t h t h e t h e o r y o f Ross and Young who used l i q u i d p e r t u r b a t i o n t h e o r y t o d e t e r m i n e an e f f e c t i v e i n t e r a t o m i c p o t e n t i a l s 1 The c a l c u l a t e d temperatures, 1200K a t 1 6 GPa and 21000K a t 5 6 GPa, a r e comparable t o t e m p e r a t u r e s i n t h e envelopes o f J u p i t e r and Saturn.

S i 0 2 a e r o g e l i s a t r a n s p a r e n t g l a s s s t r u c t u r e w i t h a p o r e s i z e o f 10 nm and a d e n s i t y o f 0.13 g/cm3, 2 0 - f o l d expanded r e l a t i v e t o t h e d e n s i t y o f a - q u a r t z . We have o b t a i n e d H u g o n i o t d a t a f o r t h i s m a t e r i a l t o 15 GPa and 7 - f o l d compression, w h i c h i s s t i l l a 3 - f o l d volume e x p a n s i o n r e l a t i v e t o a - q u a r t z . A shock t e m p e r a t u r e of 10,800K was measured p y r o m e t r i c a l l y a t 6.7 GPa. The d a t a 2 a r e shown i n F i g . 1, p l o t t e d w i t h t h e r e s u l t s f o r

c r y s t a l 1 in e a - q u a r t z . 3 E q u a t i o n - o f - s t a t e d a t a f o r t h i s m a t e r i a l may l e a d t o an u n d e r s t a n d i n g o f c r a t e r i n g phenomena i n d u c e d b y h y p e r v e l o c i t y impact, b o t h because S i 0 2 i s an abundant g e o l o g i c a l m a t e r i a l and because a e r o g e l c a n b e used t o d i a g n o s e s t a t e s i n o t h e r m i n e r a l s r e l e a s i n g f r o m 100 GPa shock p r e s s u r e s .

/a-quartz hugoniot

1 2 3 4 5

Volume relative to a-quartz

F i g . 1 - E q u a t i o n - o f - s t a t e and shock t e m p e r a t u r e d a t a f o r shocked S i 0 2 a e r o g e l , i n i t i a l 1 y 2 0 - f o l d expanded r e l a t i v e t o a - q u a r t z . A l s o shown i s t h e H u g o n i o t of a - q u a r t z (Ref. 3).

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1984820

J O U R N A L DE PHYSIQUE

New e q u a t i o n - o f - s t a t e d a t a were measured f o r l i q u i d N2 s i n g l e - and double-shocked t o p r e s s u r e s up t o 100 GPa, compressions up t o 4 - f o l d o v e r i n i t i a l l i q u i d d e n s i t y , and i n t e r n a l e n e r g i e s up t o 1 ~ ~ / m o l e . 4 A new

s i n g l e - s h o c k p o i n t a t 80 GPa shows t h a t t h e s o f t e n i n g i n t h e n i t r o g e n Hugoniot a t 3 0 GPa i s f o l l o w e d b y a s t i f f e n i n g a t 50 GPa---a shape s i m i l a r t o H u g o n i o t s o f m a t e r i a l s undergoing phase t r a n s i t i o n s . The d a t a a r e shown i n F i g . 2, p l o t t e d w i t h p r e v i o u s r e s u l t s f o r n i t r 0 ~ e n 5 . 6 and carbon monoxide. T h r e e double-shock d a t a p o i n t s l i e above t h e p r i n c i p a l H u g o n i o t i n pressure-volume space. T h i s o b s e r v a t i o n i s t h e f i r s t i n condensed m a t t e r of double-shock p r e s s u r e g r e a t e r t h a n s i n g l e - s h o c k p r e s s u r e a t t h e same volume, and i m p l i e s t h a t p r e s s u r e i n c r e a s e s w i t h d e c r e a s i n g t e m p e r a t u r e a t c o n s t a n t volume. These anomalous double-shock p o i n t s a r e caused b y a c o n t i n u o u s phase t r a n s i t i o n . By comparing t h e p r i n c i p a l H u g o n i o t s of l i q u i d N2 and i s o e l e c t r o n i c coy7 ^{t h e}

phase t r a n s i t i o n i s i d e n t i f i e d as m o l e c u l a r d i s s o c i a t i o n . P r e l i m ' n a r y d a t a show t h a t n i t r o g e n has an e l e c t r i c a l c o n d u c t i v i t y o f 10 (ohm-cm)- 'I a t 40 GPa shock pressure, a s i g n i f i c a n t i n c r e a s e f r o m i t s i n i t i a l i n s u l a t i n g s t a t e . E s t i m a t e d shock t e m p e r a t u r e s o f > 6 , 0 0 0 ~ 8 i n d i c a t e n i t r o g e n i s i n t h e f l u i d phase i n t h e s e experiments. The t e m p e r a t u r e s a r e comparable t o t h o s e p r e d i c t e d f o r t h e i n t e r i o r s of Uranus and Neptune. The d i s s o c i a t i o n o f shocked l i q u i d N2 and NH3 suggest t h a t , i f n i t r o g e n e x i s t s i n t h e o u t e r p l a n e t s , i t e x i s t s i n more phases t h a n s i m p l y NH3.

Relative volume, V/V,

F i g . 2 - H u g o n i o t s f o r l i q u i d N2 ( t r i a n g l e a t 80 GPa i s t h i s work, s o l i d c i r c l e s f r o m Ref. 6, squares f r o m Ref. 5 ) and CO (open c i r c l e s f r o m Ref. 7 ) . The dash-dot c u r v e i s e x t r a p o l a t i o n o f l o w - p r e s s u r e common c u r v e f o r b o t h N2 and CO.

ACKNOWLEDGEMENT

Work performed under t h e auspices o f t h e U.S. Department o f Energy b y Lawrence

L i v e r m o r e N a t i o n a l L a b o r a t o r y under c o n t r a c t #W-7405-Enq-48 w i t h p a r t i a l

s u p p o r t f r o m t h e U.S. N a t i o n a l A e r o n a u t i c s & Space A d m i n i s t r a t i o n under

C o n t r a c t 83-033.

REFERENCES

1 ) NELLIS, W. J., HOLMES, N. C., MITCHELL, A. C., TRAINOR, R. J., GOVERNO, G. K., ROSS, M. and YOUNG, D. A., Lawrence L i v e r m o r e N a t i o n a l L a b o r a t o r y , UCRL-91245 ( 1984)

2 ) HOLMES, N. c., RAOOUSKY, H. B., MOSS, M. J. and NELLIS, W. J., Appl.

Phys. Lett., i n p r e s s

3 ) WACKERLE, J., J. Appl. P h y s . 3 (1962) 922

4 ) NELLIS, W. J., HOLMES, N. C., MITCHELL, A. C. and VAN THIEL, M., Lawrence L i v e r m o r e N a t i o n a l L a b o r a t o r y , UCRL-90625 (1984)

5 ) ZUBAREV, V. N. and TELEGIN, G. S., Sov. Phys. Dokl. 7 (1962) 34 6 ) NELLIS, W. J. and MITCHELL, A. C., J. Chem. Phys. s - ( 1 9 8 0 ) 6137 7 ) NELLIS, W. J.. REE, F. H., VAN THIEL, M. and MITCHELL, A. C., J. Chem.

Phys. 3 (1981) 3055

8 ) JOHNSON, J. D., SHAM, M. S. and HOLIAN, 8. L., J. Chem. Phys. 80 (1984)

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