Ulysses Solar Corona Experiment (SCE) The Ulysses dual-frequency radio subsystem was utilized by the Ulysses Solar Corona Experiment (SCE) to measure the electron content (column density) and its variations during the first solar conjunction (C1) of the Ulysses mission in the summer of 1991 as well as the fourth solar conjunction (C4) in the winter of 1995. In the nominal mode for radio-sounding observations [BIRDETAL1992A], both downlinks (S-band: f_s = 2.3 GHz; X-band: f_x = 8.4 GHz) are phase coherent with the uplink (S-band: f_u = 2.1 GHz). The dual-frequency radio-sounding technique exploits the dispersive nature of ionized media on the propagation of the two downlinks. The tiny Doppler shift due to plasma moving in and out of the ray path is greater at S-band than at the higher frequency X-band. Similarly, because the group velocity of waves propagating in ionized media is smaller for lower frequencies, the round-trip time of propagation for coded range signals between the spacecraft and the ground station will be longer at S-band than at X-band. SCE Data Types The SCE data are obtained from the Radio Science Support group at JPL [ASMAR&RENZETTI1993; ASMARETAL1995]. There are basically two types of data: ranging and Doppler (Frequency), recorded at the tracking sites of the NASA Deep Space Network (DSN) as a function of UT Ground Received Time [DSN810-5]. The raw data are delivered in special binary files called ATDFs (Archival Tracking Data Files), containing ranging and Doppler data from the standard DSN tracking receivers. There are high time resolution Doppler data from special radio science receivers (so-called 'open loop' data) as well. These are in files called ODRs (Original Data Records). ATDFs are files of radiometric data produced by the Network Operations Control Center (NOCC) Navigation Subsystem (NAV). They are derived from Intermediate Data Records by NAV and contain all radiometric measurements received from the DSN station including signal levels (`AGC' = automatic gain control in dBm), antenna pointing angles, frequency (often referred to simply as `Doppler'), range, and residuals. Doppler data are often used to infer spacecraft radial motion relative to the tracking antenna. Data values in ATDFs are reported at rates no higher than 10 per second. For the Ulysses solar conjunction C1 the received frequencies at S-Band and X-band were recorded at a nominal sample time of one per second. Ranging data were recorded nominally at intervals of ca. 10 minutes. Each ATDF data record contains 117 parameters, stored in records of 288 bytes. The ATDF is described in section TRK-2-25 of the JPL Document 820-13 [DSN820-13]. SCE Data Recording Opportunities The ranging data from the ATDFs have been analyzed for the solar conjunction C1 and a number of publications describe the results [PAETZOLDETAL1992; BIRDETAL1994; WOOETAL1995A; WOOETAL1995B; WOO1996; PAETZOLDETAL1997]. Ranging results from the geometrically unique fourth Ulysses solar conjunction (C4) are also available [PAETZOLDETAL1995; BIRDETAL1996; WOO&HABBAL1997; PAETZOLD&BIRD1998; WOO&HABBAL1998]. Coronal velocities as a function of solar distance were derived from the C1 Doppler data using a correlation technique between uplink and downlink [WOHLMUTHETAL1997] and between two simultaneously tracking ground stations [JANARDHANETAL1999]. Differences in the spectral characteristics of electron density fluctuations observed in coronal holes vs. corona streamers were reported from analyses of the C4 Doppler data [PAETZOLDETAL1996; KARLETAL1997]. The Ulysses radio subsystem was utilized during the Jupiter encounter to measure the columnar electron density of the Io Plasma Torus [BIRDETAL1992B; BIRDETAL1993]. These data, together with all Ulysses results from the Jupiter encounter, are archived at the Planetary Data System (PDS). SCE Ranging Data Processing Data files have been generated which contain the ranging data at an advanced stage of processing. After stripping the ranging data from the ATDFs and weeding out obviously bad data, tables of the measured data plus physically relevant quantities were produced for the archive as function of time. Ranging data during the Ulysses solar conjunctions C1 (7 August to 5 September 1991) and C4 (23 February to 14 March 1995) have been provided to this archive in the RANGE_C1.TXT and RANGE_C4.TXT files. As an example, the first few lines of RANGE_C1.TXT are as follows: year mo dd hh:mm:ss set no dss difrng econt 1991- 8- 7T 1:11:23.712Z 1 1 43 557 2227 1991- 8- 7T 1:21:24.192Z 1 2 43 555 2219 1991- 8- 7T 1:31:24.672Z 1 3 43 567 2267 1991- 8- 7T 1:41:24.288Z 1 4 43 575 2299 1991- 8- 7T 1:51:23.904Z 1 5 43 578 2311 1991- 8- 7T 2: 1:23.520Z 1 6 43 574 2295 1991- 8- 7T 2:11:24.000Z 1 7 43 567 2267 1991- 8- 7T 2:21:23.616Z 1 8 43 575 2299 1991- 8- 7T 2:31:23.232Z 1 9 43 584 2335 1991- 8- 7T 2:41:23.712Z 1 10 43 570 2279 1991- 8- 7T 2:51:24.192Z 1 11 43 572 2287 1991- 8- 7T 3: 1:24.672Z 1 12 43 582 2327 1991- 8- 7T 3:11:24.288Z 1 13 43 591 2363 1991- 8- 7T 3:31:23.520Z 1 14 43 596 2383 1991- 8- 7T 3:41:24.000Z 1 15 43 588 2351 where: year : 1991 mo : month of year dd : day of month hh:mm:ss : hours, minutes seconds (UT, ground received) set : running no. for each DSN tracking pass during C1, C4, resp. no : running no. for range measurement within each tracking pass dss : DSN station number difrng : differential range delay in `range units' (RU) [DSN810-5] econt : electron content in `hexems' [BIRDETAL1992A; BIRDETAL1994] note: difrng (RU) and econt (hexems) are given to the nearest respective unit. The estimated accuracy of a differential range measurement is of the order of 50 range units. The following table gives information about the size and coverage of the Ulysses SCE ranging data set from the two solar conjunctions: Conj Year start stop ascii size gzip size mo:dd:hh:mm mo:dd:hh:mm (kB) (kB) C1 1991 08:07:01:11 09:05:17:55 88 20 C4 1995 02:23:05:06 03:14:14:06 145 33 SCE Doppler Data Processing Data files have been generated from the ATDFs which contain the quantities of interest for analysis of the Ulysses downlink frequencies. The data set for the first solar conjunction C1 in 1991 from DOY 218-248 (6 August to 5 September) consists of the following files : DOP91218.063.gz DOP91227.012.gz DOP91235.043.gz DOP91242.014.gz DOP91219.043.gz DOP91227.043.gz DOP91235.063.gz DOP91242.043.gz DOP91219.061.gz DOP91227.063.gz DOP91236.014.gz DOP91243.014.gz DOP91220.043.gz DOP91228.014.gz DOP91236.043.gz DOP91243.063.gz DOP91221.014.gz DOP91228.063.gz DOP91237.014.gz DOP91244.014.gz DOP91221.043.gz DOP91229.014.gz DOP91237.063.gz DOP91244.063.gz DOP91221.143.gz DOP91229.043.gz DOP91238.014.gz DOP91245.014.gz DOP91222.014.gz DOP91229.063.gz DOP91238.043.gz DOP91245.063.gz DOP91222.043.gz DOP91230.014.gz DOP91238.063.gz DOP91246.014.gz DOP91223.014.gz DOP91230.063.gz DOP91239.014.gz DOP91246.043.gz DOP91223.043.gz DOP91231.014.gz DOP91239.043.gz DOP91247.014.gz DOP91224.014.gz DOP91231.063.gz DOP91239.063.gz DOP91248.014.gz DOP91224.063.gz DOP91232.014.gz DOP91240.014.gz DOP91248.043.gz DOP91225.014.gz DOP91233.014.gz DOP91240.063.gz datalist.c1 DOP91225.063.gz DOP91234.014.gz DOP91241.012.gz DOP91226.014.gz DOP91234.043.gz DOP91241.043.gz DOP91226.063.gz DOP91234.063.gz DOP91241.063.gz The data set for the fourth solar conjunction C4 in 1995 from DOY 53-73 (22 February to 14 March) consists of the following files : DOP95053.042.gz DOP95057.042.gz DOP95063.042.gz DOP95069.012.gz DOP95054.012.gz DOP95057.061.gz DOP95063.061.gz DOP95069.042.gz DOP95054.061.gz DOP95057.142.gz DOP95064.061.gz DOP95069.061.gz DOP95054.161.gz DOP95057.161.gz DOP95065.042.gz DOP95070.042.gz DOP95055.042.gz DOP95058.061.gz DOP95065.061.gz DOP95070.061.gz DOP95055.061.gz DOP95059.042.gz DOP95065.142.gz DOP95071.012.gz DOP95055.142.gz DOP95059.061.gz DOP95066.042.gz DOP95071.042.gz DOP95055.161.gz DOP95060.042.gz DOP95066.061.gz DOP95071.061.gz DOP95056.012.gz DOP95060.061.gz DOP95067.012.gz DOP95072.042.gz DOP95056.042.gz DOP95061.012.gz DOP95067.042.gz DOP95072.061.gz DOP95056.061.gz DOP95061.042.gz DOP95067.061.gz DOP95073.042.gz DOP95056.161.gz DOP95062.042.gz DOP95068.012.gz DOP95073.061.gz DOP95057.012.gz DOP95062.061.gz DOP95068.042.gz datalist_c4.txt The "gz" suffex means that these files have been compressed with the UNIX gzip utility. They can be expanded to ascii tables with the analog gunzip utility. Each file contains dual-frequency Doppler data at a sample rate of 1 point per second from each tracking pass. The filename provides the day-of-year (doy) and ground tracking station (dss) according to the scheme "DOPyydoy.dss", where the year number is yy = 91 (C1) or 95 (C4). The doy given to each file applies to the start of the data recording. The deep space stations of the NASA Deep Space Network (DSN) used for SCE are: DSS 12 : Goldstone 34-m DSS 14 : Goldstone 70-m DSS 42 : Canberra 34-m DSS 43 : Canberra 70-m DSS 61 : Madrid 34-m DSS 63 : Madrid 70-m Some tracking passes, especially at the Canberra stations, continue on into the next doy. Normally, a "0" preceeds the dss number. The few cases with a "1" rather than "0" are a separate tracking pass at the same dss later on the same doy. The files "datalist_c1.txt" and "datalist_c4.txt" contain listings of each tracking pass with such information as date, ATDF number, start and end times of pass, start and end times of data recording, pass duration, station overlaps, etc. Each file contains 15 columns per data point defined as follows: column explanation 1-4 : time tag (UT, ground received) 1 : DOY in 1991 (C1) or 1995 (C4) 2 : HH 3 : MM 4 : SS 5 : DSS 6 : uplink frequency [Hz] 7-10 : S-band receiver parameters 7 : agc [dBm] 8 : downlink frequency [Hz] 9 : downlink frequency residual [Hz] 10 : total slipped cycles during count 11-14 : X-band receiver parameters 11 : agc [dBm] 12 : downlink frequency [Hz] 13 : downlink frequency residual [Hz] 14 : total slipped cycles during count 15 : differential Doppler from Counts A more detailed explanation of the parameters is given in section TRK-2-15 of the JPL Document 820-13 [DSN820-13]. The total volume of validated SCE Doppler data in the archive is given for both conjunctions in the following table. conjunction # passes # hours # hours total MB total MB total overlap (ASCII) (binary compressed) C1 ingress 30 169.4 12.2 74.0 14.9 egress 34 201.0 14.4 87.8 17.5 total 64 370.4 26.6 161.8 32.4 C4 ingress 27 188.2 5.1 73.8 14.8 egress 24 194.0 7.5 76.0 15.2 total 51 382.2 12.6 149.8 30.0 ---------------------------------------------------------------------- C1+C4 115 752.6 39.2 311.6 62.4 References ASMARETAL1995 Asmar, S.W., R.G. Herrera, and T. Priest, Radio Science Handbook, JPL D-7938 Volume 6, Jet Propulsion Laboratory, Pasadena, CA, 1995. ASMAR&RENZETTI1993 Asmar, S.W., and N.A. Renzetti, The Deep Space Network as an Instrument for Radio Science Research, Jet Propulsion Laboratory Publication 80-93, Rev. 1, 15 April 1993. BIRDETAL1992A Bird, M.K., S.W. Asmar, J.P. Brenkle, P. Edenhofer, M. Paetzold, and H. Volland, The coronal-sounding experiment, Astron. Astrophys. Supp. Ser. 92, 425-430, 1992a. BIRDETAL1992B Bird, M.K., S.W. Asmar, J.P. Brenkle, P. Edenhofer, O. Funke, M. Paetzold, and H. Volland, Ulysses radio occultation observations of the Io plasma torus during the Jupiter encounter, Science 257, 1531-1535, 1992b. BIRDETAL1993 Bird, M.K., S.W. Asmar, P. Edenhofer, O. Funke, M. Paetzold, and H. Volland, The structure of Jupiter's Io plasma torus inferred from Ulysses radio occultation observations, Planet. Space Sci. 41, 999-1010, 1993. BIRDETAL1994 Bird, M.K., H. Volland, M. Paetzold, P. Edenhofer, S,W, Asmar, and J.P. Brenkle, The coronal electron density distribution determined from dual-frequency ranging measurements during the 1991 solar conjunction of the {\sl Ulysses} spacecraft, Astrophys. J. 426, 373-381, 1994. BIRDETAL1996 Bird, M.K., M. Paetzold, M., P. Edenhofer, S.W. Asmar, and T.P. McElrath, Coronal radio sounding with Ulysses: solar wind electron density near 0.1 AU during the 1995 conjunction, Astron. Astrophys. 316, 441-448, 1996. DSN810-5 Deep Space Network / Flight Project Interface Design Book, Document 810-5, Jet Propulsion Laboratory, Pasadena, CA. DSN820-13 Deep Space Network System Requirements / Detailed Interface Design, Document 820-13, Jet Propulsion Laboratory, Pasadena, CA. JANARDHANETAL1999 Janardhan, P., M.K. Bird, P. Edenhofer, R. Wohlmuth, D. Plettemeier, S.W. Asmar, M. Paetzold, and J. Karl, Coronal velocity measurements with Ulysses: Multi-link correlation studies during two superior conjunctions, Solar Phys., in press, 1999. KARLETAL1997 Karl, J., M. Paetzold and M.K. Bird, Coronal radio sounding: Non-Gaussian turbulence in the source regions of slow and fast solar wind, Geophys. Res. Lett. 24, 2881-2884, 1997. PAETZOLD&BIRD1998 Paetzold, M., and M.K. Bird, Polar plumes and fine-scale coronal structures - On the interpretation of coronal radio sounding data, Geophys. Res. Lett. 25, 1845-1848, 1998. PAETZOLDETAL1992 Paetzold, M., M.K. Bird, H. Volland, P. Edenhofer, S.W. Asmar, and J.P. Brenkle, Coronal sounding with Ulysses: Preliminary results from the first solar conjunction, in Solar Wind Seven, E. Marsch and R. Schwenn (eds.), Pergamon Press, Oxford, 237-240, 1992. PAETZOLDETAL1995 Paetzold, M., M.K. Bird, P. Edenhofer, S.W. Asmar, and T.P. McElrath, Dual-frequency radio sounding of the solar corona during the 1995 conjunction of the Ulysses spacecraft, Geophys. Res. Lett. 22, 3313-3316, 1995. PAETZOLDETAL1996 Paetzold, M., J. Karl, and M.K. Bird, Coronal radio sounding with Ulysses: Dual-frequency phase spectra in coronal holes and streamers, Astron. Astrophys. 316, 449-456, 1996. PAETZOLDETAL1997 Paetzold, M., B.T. Tsurutani and M.K. Bird, An estimate of large-scale solar wind density and velocity profiles in a coronal hole and the coronal streamer belt, J. Geophys. Res. 102, 24,151-24,160, 1997. WOHLMUTHETAL1997 Wohlmuth, R., D. Plettemeier, P. Edenhofer, M.K. Bird, M. Paetzold and S.W. Asmar, Measurement of the propagation speed of plasma inhomogeneities in the solar corona using an uplink/downlink correlation method, Radio Sci. 32, 617-628, 1997. WOO1996 Woo, R., Detection of low-latitude plumes in the outer corona by Ulysses radio ranging measurements, Astrophys. J. 464, L95-L98, 1996. WOO&HABBAL1997 Woo, R., and S.R. Habbal, Extension of coronal structure into interplanetary space, Geophys. Res. Lett. 24, 1159-1162, 1997. WOO&HABBAL1998 Woo, R., and S.R. Habbal, Comment on: "Polar plumes and fine-scale coronal structures - On the interpretation of coronal radio sounding data" by Paetzold and Bird, Geophys. Res. Lett. 25, 1849-1850, 1998. WOOETAL1995A Woo, R., J.W. Armstrong, M.K. Bird and M. Paetzold, Variation of fractional electron density fluctuations inside 40 R_s observed by Ulysses ranging measurements, Geophys. Res. Lett. 22, 329-332, 1995a. WOOETAL1995B Woo, R., J.W. Armstrong, M.K. Bird and M. Paetzold, Fine-scale filamentary structure in coronal streamers, Astrophys. J. 449, L91-L94, 1995b.