- Email: [email protected]
E.u.v. observations of solar flares from Mars
Plunri Spoir~Sc'/. Vol.39.No. I:?. pp.39-40. lY91 PrmtrdInGreatRrilain
E.U.V.
OBSERVATIONS
T. V. KAZACHEVSKAYA,
Fedorov
OO32Xl633/Yl $300+000 Pergamon Press plc
Institute
of Applied
OF SOLAR MARS
L. L. BUKUSOVA,
FLARES
D. A. GONYUKH,
FROM
A. 1. LOMOVSKY
and YU. N. TSYGELNITSKY Geophysics. Glebovskaya, 20-b, 107258. Moscow,
U.S.S.R.
(Rrcehwi 22 June 1990) Abstract-Results
of solar flare e.u.v. observations
in March
1989 are presented.
The observations
have
been performed by the SUFR equipment aboard the spacecraft (SC) Phobos 2 orbiting Mars.
as the monitoring of the detector background and instrument sensitivity. The SUFR equipment calibrated beforehand was installed aboard the SC Phbos 1.2 and launched on 7 and I2 July 1988, respectively. The equipment began working on the first day the spacecraft was injected into orbit. The information from SC Phobos 1 was received up to 29 August 1988, and that from SC Plzobos %-over the whole flight route Earth-Mars and near Mars-up to March 1989. According to the flight programme, measurements were taken every day from 18:X to 19:25 U.T. For the first time data were obtained on the e.u.v. flux from the SC Phohos orbiting Mars at about 239,OOO.OOOkm away from the Sun and about 265,000,OOO km from the Earth. Table 1 shows e.u.v. emission intensity for five observation days in March 1989. Each date is characterized by mean hourly measurements of solar emission intensity in the H L, line, distance between the SC Plmhos 2 and the Sun, Mars and Phobos on that day. as well as by HL emission intensity and solar emission flux at i < 130 nm, both reduced to 1 a.u. Large solar flares on 8-l 1 March 1989 were recorded by SUFR equipment aboard the SC Plzohos 2, which was then orbiting Mars at about 9700 km at about 9000-18,000 km from Phobos. At that time
Data on the intensity of extreme U.V. solar emission were obtained on a daily basis within the framework of the International Project “PHOBOS”. The measurements were performed using the SUFR (solar ultraviolet radiometer) equipment for recording the solar emission flux at 1 < 130 nm based on the thermoluminescent technique. The technique provides absolute measurements within the above spectral range using CaSO, (Mn) thermophosphorus (Kazachevskaya et al., 1985). In 1984-3985, jointly with VNIIOFl*. a technique was developed on absolute calibration by synchrotron radiation (Anevsky et al.. 1987) by secondary references. A series of observations were carried out to determine relative sensitivity of the equipment in the range 100-140 nm and absolute calibration is performed by resonance luminosity lines ii, I 15.6, 123.6 and 129.6 nm. The absolute calibration error does not exceed 15% of the measured value. Every 2 min the instrument’s operation cycle allows one to obtain information on the total solar emission flux at j. < I30 nm. measure the H L, line emission (i. = 121.6 nm) and the emission at i. d IO nm and i G 15 nm. as well *All-Union
Institute
for Optical
and Physical
Measure-
ments. Moscow.
TARLE
I, near Phobos (ergcm-‘s
Date 8 9 IO I1 23
March March March March March
1989 1989 1989 1989 1989
2.8 2.8 3.1 3.3 2.7
~‘)
1. E.U.V.
Sun SC
EMISSION FLUX MEASUREMENTS
Distance (km) Mars Phobos SC SC
236.6. IOh 236.8. 1Oh 236.9. IO6 237.1. IO0 239.07.10”
9675 9677 9678 9682 9265 39
9272 15.687 18,925 14.344 41
Intensity near the Earth 1< 130nm 1,. (ergcm-‘s-l) (erg cm” s- ‘) 7.0 7.0 7.7 8.2 6.9
11.4 I I.5 12.6 11.3 II.3
40
T. V. KAZACHEVSKAYA et al. TABLE 2. E.U.V. FLAKESRECOKDEDIN MARCH 1989 BY SC Phobos E.U.V.
Time of recording Date 8 March 9 March
1989 1989
10 March
1989
11 March
1989
by the SC equipment (U.T.)
Observations X-ray class
from the Earth Optical
11% 16.5%
M4.6
Sub.
18:37-18:40 19:1619:18
10% 11.5%
Ml.2
SF 1B
19:08 to the end of the measurements
Double increase
x4.5
3B
16%
Ml.2
IN
From
18:24
class
-
18:31-18:36 19:08-19:12
e.u.v. emission flux near the Earth (with a measurement error not higher than 5-7%) was 11.512.5 erg cm-’ s-’ at I < 130 nm and 7-8 erg cm- ’ s _ ’ in the H L, line. Table 2 presents dates and times (U.T.) of solar flares recorded by the SUFR equipment, e.u.v. emission flux increase (per cent) relative to the undisturbed level, as well as the X-ray class and optical class of flares observed from the Earth at the time (Solar Gecydzysical Data, 1989). The angle between the Sun, the Earth and the SC at Mars is 57’. This means that the SUFR equipment was in a position to see flares related to groups of spots 45 days before their appearance at the Sun side visible from the Earth. It can refer to the phenomenon observed on 8 March 1989 at 18:30 U.T. The analysis of the information obtained makes it possible to state that a significant (approximately double) increase in e.u.v. emission intensity of a solar flare observed on 10 March 1989 is associated with a considerable increase in the X-ray emission flux (class 4.5). the solar
emission increase (A < 130nm)
In conclusion it should be noted that the character of the increased e.u.v. emission flux of the solar flares recorded from Mars agrees, on the whole, with earlier observations carried out by satellites Solrad II and Prognoz 7 near the Earth (Horan and Kreplin, 1981; Horan et al., 1983 ; Kazachevskaya et al., 1986).
REFERENCES
Anevsky, S. I., Burov, G. V., Verny, A. E. et al. (1987) Phys. Scriptu 35, 623. Horan, D. M. and Kreplin, R. W. (1981) Solur P/ZJX 74, 265. Horan, D. M., Kreplin. R. W. and Dere. K. P. (1983) Solar Phys. 85. 303. Kazachevskaya. T. V., Bruyevich, Ye. A. and IvanovKholodny, G. S. (1986) Solnechnge Darznye No. 3, 68. Kazachevskaya, T. V., Ivanov-Kholodny, G. S. and Gonjukh, D. A. (1985) Geomayrt. Aeronomiu 25,995. Solar Geophysical Duta (1989) No. 536, p. 1.
E.U.V.
OBSERVATIONS
T. V. KAZACHEVSKAYA,
Fedorov
OO32Xl633/Yl $300+000 Pergamon Press plc
Institute
of Applied
OF SOLAR MARS
L. L. BUKUSOVA,
FLARES
D. A. GONYUKH,
FROM
A. 1. LOMOVSKY
and YU. N. TSYGELNITSKY Geophysics. Glebovskaya, 20-b, 107258. Moscow,
U.S.S.R.
(Rrcehwi 22 June 1990) Abstract-Results
of solar flare e.u.v. observations
in March
1989 are presented.
The observations
have
been performed by the SUFR equipment aboard the spacecraft (SC) Phobos 2 orbiting Mars.
as the monitoring of the detector background and instrument sensitivity. The SUFR equipment calibrated beforehand was installed aboard the SC Phbos 1.2 and launched on 7 and I2 July 1988, respectively. The equipment began working on the first day the spacecraft was injected into orbit. The information from SC Phobos 1 was received up to 29 August 1988, and that from SC Plzobos %-over the whole flight route Earth-Mars and near Mars-up to March 1989. According to the flight programme, measurements were taken every day from 18:X to 19:25 U.T. For the first time data were obtained on the e.u.v. flux from the SC Phohos orbiting Mars at about 239,OOO.OOOkm away from the Sun and about 265,000,OOO km from the Earth. Table 1 shows e.u.v. emission intensity for five observation days in March 1989. Each date is characterized by mean hourly measurements of solar emission intensity in the H L, line, distance between the SC Plmhos 2 and the Sun, Mars and Phobos on that day. as well as by HL emission intensity and solar emission flux at i < 130 nm, both reduced to 1 a.u. Large solar flares on 8-l 1 March 1989 were recorded by SUFR equipment aboard the SC Plzohos 2, which was then orbiting Mars at about 9700 km at about 9000-18,000 km from Phobos. At that time
Data on the intensity of extreme U.V. solar emission were obtained on a daily basis within the framework of the International Project “PHOBOS”. The measurements were performed using the SUFR (solar ultraviolet radiometer) equipment for recording the solar emission flux at 1 < 130 nm based on the thermoluminescent technique. The technique provides absolute measurements within the above spectral range using CaSO, (Mn) thermophosphorus (Kazachevskaya et al., 1985). In 1984-3985, jointly with VNIIOFl*. a technique was developed on absolute calibration by synchrotron radiation (Anevsky et al.. 1987) by secondary references. A series of observations were carried out to determine relative sensitivity of the equipment in the range 100-140 nm and absolute calibration is performed by resonance luminosity lines ii, I 15.6, 123.6 and 129.6 nm. The absolute calibration error does not exceed 15% of the measured value. Every 2 min the instrument’s operation cycle allows one to obtain information on the total solar emission flux at j. < I30 nm. measure the H L, line emission (i. = 121.6 nm) and the emission at i. d IO nm and i G 15 nm. as well *All-Union
Institute
for Optical
and Physical
Measure-
ments. Moscow.
TARLE
I, near Phobos (ergcm-‘s
Date 8 9 IO I1 23
March March March March March
1989 1989 1989 1989 1989
2.8 2.8 3.1 3.3 2.7
~‘)
1. E.U.V.
Sun SC
EMISSION FLUX MEASUREMENTS
Distance (km) Mars Phobos SC SC
236.6. IOh 236.8. 1Oh 236.9. IO6 237.1. IO0 239.07.10”
9675 9677 9678 9682 9265 39
9272 15.687 18,925 14.344 41
Intensity near the Earth 1< 130nm 1,. (ergcm-‘s-l) (erg cm” s- ‘) 7.0 7.0 7.7 8.2 6.9
11.4 I I.5 12.6 11.3 II.3
40
T. V. KAZACHEVSKAYA et al. TABLE 2. E.U.V. FLAKESRECOKDEDIN MARCH 1989 BY SC Phobos E.U.V.
Time of recording Date 8 March 9 March
1989 1989
10 March
1989
11 March
1989
by the SC equipment (U.T.)
Observations X-ray class
from the Earth Optical
11% 16.5%
M4.6
Sub.
18:37-18:40 19:1619:18
10% 11.5%
Ml.2
SF 1B
19:08 to the end of the measurements
Double increase
x4.5
3B
16%
Ml.2
IN
From
18:24
class
-
18:31-18:36 19:08-19:12
e.u.v. emission flux near the Earth (with a measurement error not higher than 5-7%) was 11.512.5 erg cm-’ s-’ at I < 130 nm and 7-8 erg cm- ’ s _ ’ in the H L, line. Table 2 presents dates and times (U.T.) of solar flares recorded by the SUFR equipment, e.u.v. emission flux increase (per cent) relative to the undisturbed level, as well as the X-ray class and optical class of flares observed from the Earth at the time (Solar Gecydzysical Data, 1989). The angle between the Sun, the Earth and the SC at Mars is 57’. This means that the SUFR equipment was in a position to see flares related to groups of spots 45 days before their appearance at the Sun side visible from the Earth. It can refer to the phenomenon observed on 8 March 1989 at 18:30 U.T. The analysis of the information obtained makes it possible to state that a significant (approximately double) increase in e.u.v. emission intensity of a solar flare observed on 10 March 1989 is associated with a considerable increase in the X-ray emission flux (class 4.5). the solar
emission increase (A < 130nm)
In conclusion it should be noted that the character of the increased e.u.v. emission flux of the solar flares recorded from Mars agrees, on the whole, with earlier observations carried out by satellites Solrad II and Prognoz 7 near the Earth (Horan and Kreplin, 1981; Horan et al., 1983 ; Kazachevskaya et al., 1986).
REFERENCES
Anevsky, S. I., Burov, G. V., Verny, A. E. et al. (1987) Phys. Scriptu 35, 623. Horan, D. M. and Kreplin, R. W. (1981) Solur P/ZJX 74, 265. Horan, D. M., Kreplin. R. W. and Dere. K. P. (1983) Solar Phys. 85. 303. Kazachevskaya. T. V., Bruyevich, Ye. A. and IvanovKholodny, G. S. (1986) Solnechnge Darznye No. 3, 68. Kazachevskaya, T. V., Ivanov-Kholodny, G. S. and Gonjukh, D. A. (1985) Geomayrt. Aeronomiu 25,995. Solar Geophysical Duta (1989) No. 536, p. 1.