IMAGE RPI Whistler Mode Experiments

IMAGE

RPI Whistler Mode Experiments

RPI Whistler Mode Experiments

Image of IMAGE in space

The IMAGE Team is continuing to perform propagation to VLF ground receiving stations and satellite instruments. We invite the interest of all in what we are doing, whether involved in theory, satellite observations, or ground work. Persons involved in whistler-mode planning for IMAGE include Bill Taylor, Don Carpenter, Vikas Sonwalkar, Tim Bell, and Maria Salvati.



Special Whistler Mode Experiments with the IMAGE Satellite A special campaign of whistler-mode transmissions from the IMAGE satellite will be from November 21 to December 4, 2001 and will be conducted at the times given in the table at the bottom of this message. The Radio Plasma Imager instrument on IMAGE, called RPI, normally operates at distances up to apogee at about 8 Earth Radii by radio sounding at frequencies ranging from 3 kHz to 3 MHz. When IMAGE is near perigee, either inside the plasmasphere or at low altitudes over the southern hemisphere polar regions, some of the signals launched between 3 kHz and about 500 kHz may propagate in the whistler mode, depending upon the local plasma parameters. An outstanding problem to be investigated under these conditions concerns whistler-mode propagation from an in situ source to the ground. It is not expected that detection of RPI signals on the ground will be a common occurrence, and the conditions under which such detection may occur will be of great scientific interest. Ground observers are therefore strongly encouraged to participate in the upcoming campaign and in future campaigns that will hopefully be scheduled. There will be two sets of experiments, at 5-15 kHz (VLF) and at 130 and 380 kHz. The 5-15 kHz experiments will be performed on the incoming (towards perigee), southward traveling part of every orbit, starting at about the point where the magnetic field line through the satellite is at about 50 degrees N latitude. They will continue until the the 130 and 380 kHz experiment begins. The 130 and 380 kHz transmissions will begin when the satellite is four minutes before the closest approach to the South Pole, and continue four minutes past closest approach. The format of the VLF transmissions will be 0.125 seconds on, 0.375 seconds off, at 5, 7, 9, 11, 13, and 15 kHz, repeated over and over. Details of the satellite orbit, both graphical and tabular, may be found at the Satellite Situation Center web site: http://sscweb.gsfc.nasa.gov/ SSCWeb was used to get IMAGE orbital parameters to illustrate the operations before and during the first South Pole crossing. For the VLF operation, if we had an observer in the North Pacific, somewhere between Hawaii and California, they might be in a good place to hear IMAGE. We have 23 other opportunities during the two weeks, though. Note that Longitudes are give in East Longitude, whereas in the US, we are used to using West Longitude in our hemisphere. ArcLen is the distance from the satellite to the Earth's surface along the magnetic field line. DipL-Val is the a measure of magnetic latitude of the field line. Time GEO NorthBtrace GEO Radius yyyy ddd hh:mm Lat Long Lat Long ArcLen (RE) DipL-Val Notes 2001 325 07:02 49.20 207.88 67.72 218.56 2.56 3.46 8.3 2001 325 07:04 48.13 207.41 67.08 217.97 2.50 3.40 7.8 2001 325 07:06 47.03 206.94 66.46 217.36 2.44 3.33 7.3 2001 325 07:08 45.88 206.46 65.82 216.72 2.38 3.27 6.9 2001 325 07:10 44.68 205.99 65.12 216.11 2.32 3.20 6.4 2001 325 07:12 43.43 205.52 64.40 215.49 2.26 3.13 6.0 2001 325 07:14 42.13 205.05 63.66 214.85 2.20 3.07 5.6 2001 325 07:16 40.76 204.58 62.85 214.24 2.14 3.00 5.3 2001 325 07:18 39.34 204.11 62.03 213.61 2.08 2.93 4.9 2001 325 07:20 37.84 203.64 61.14 212.99 2.02 2.86 4.6 2001 325 07:22 36.27 203.16 60.22 212.35 1.96 2.79 4.3 2001 325 07:24 34.62 202.69 59.23 211.74 1.90 2.72 4.0 2001 325 07:26 32.88 202.22 58.20 211.11 1.84 2.65 3.8 2001 325 07:28 31.04 201.75 57.10 210.50 1.78 2.57 3.5 VLF start 2001 325 07:30 29.09 201.28 55.95 209.89 1.72 2.50 3.3 2001 325 07:32 27.03 200.81 54.73 209.30 1.67 2.43 3.1 2001 325 07:34 24.84 200.34 53.44 208.71 1.61 2.35 2.9 2001 325 07:36 22.51 199.88 52.08 208.15 1.56 2.28 2.7 2001 325 07:38 20.02 199.41 50.66 207.60 1.51 2.21 2.5 2001 325 07:40 17.36 198.95 49.17 207.08 1.47 2.13 2.3 2001 325 07:42 14.51 198.48 47.64 206.61 1.43 2.06 2.2 2001 325 07:44 11.44 198.02 46.07 206.18 1.40 1.98 2.1 2001 325 07:46 8.14 197.56 44.51 205.82 1.38 1.91 1.9 2001 325 07:48 4.57 197.10 43.00 205.55 1.38 1.84 1.8 2001 325 07:50 0.72 196.65 41.62 205.41 1.39 1.77 1.8 2001 325 07:52 -3.46 196.20 40.49 205.44 1.44 1.70 1.7 2001 325 07:54 -7.99 195.75 39.73 205.70 1.52 1.63 1.7 2001 325 07:56 -12.91 195.31 39.54 206.30 1.67 1.56 1.7 2001 325 07:58 -18.23 194.88 40.10 207.35 1.90 1.50 1.7 2001 325 08:00 -24.00 194.46 41.53 209.01 2.26 1.45 1.7 2001 325 08:02 -30.22 194.06 43.90 211.47 2.82 1.39 1.9 2001 325 08:04 -36.90 193.67 47.10 214.96 3.72 1.35 2.1 2001 325 08:06 -44.00 193.32 50.92 219.73 5.23 1.31 2.5 2001 325 08:08 -51.49 193.03 55.08 226.11 8.02 1.28 3.3 2001 325 08:10 -59.27 192.82 59.24 234.54 15.08 1.26 4.6 VLF end 2001 325 08:12 -67.26 192.81 N/A N/A N/A 1.25 7.5 2001 325 08:14 -75.31 193.31 -nan0x -nan0x-nan0xf 1.25 14.2 SP start 2001 325 08:16 -83.28 196.10 -nan0x -nan0x-nan0xf 1.26 27.9 2001 325 08:18 -88.67 337.79 -nan0x -nan0x-nan0xf 1.28 32.5 South Pole 2001 325 08:20 -81.33 4.54 -nan0x -nan0x-nan0xf 1.31 19.2 2001 325 08:22 -74.21 6.16 63.98 312.26 23.35 1.34 10.8 SP end Note that during the VLF operation, the longitude remains relatively constant. In the case above the longitude of the foot of the earth's magnetic field line through the satellite only changes from 210 to 234 degrees East longitude. (The longitude of the foot of the field line is the important parameter, because the waves travel approximately along the field lines.) Over the latitudes of the US the longitude changes very little. Below is one line for each orbit at approximately a field line foot point of 50 degrees latitude, so you can identify which orbits are near your location. Time GEO NorthBtrace GEO yyyy ddd hh:mm Lat Long Lat Long ArcLen One location of longitude 2001 325 07:38 20.02 199.41 50.66 207.60 1.51 N. Pacific 2001 325 21:54 17.31 344.87 49.70 337.73 1.47 Azores Islands 2001 326 12:12 11.32 129.86 50.08 128.59 1.53 China, Japan 2001 327 02:12 29.06 279.04 49.64 277.16 1.61 West Virginia 2001 327 16:38 14.33 62.16 49.78 62.17 1.50 Uzbekistan 2001 328 06:46 22.39 209.47 50.57 217.79 1.52 N. Pacific 2001 328 21:04 17.14 354.46 50.52 348.76 1.48 Mauritania 2001 329 11:22 11.06 139.45 50.31 138.87 1.52 Japan 2001 330 01:22 29.03 288.62 49.91 284.75 1.60 New Jersey 2001 330 15:48 14.10 71.74 49.59 71.67 1.49 Afganistan 2001 331 05:54 24.66 219.52 50.54 227.46 1.54 N. Pacific 2001 331 20:16 13.98 3.57 49.52 359.36 1.45 England 2001 332 10:32 10.74 149.03 50.34 149.75 1.51 E. Australia 2001 333 00:32 28.95 298.20 50.46 292.54 1.60 Maine 2001 333 14:58 13.78 81.32 49.41 81.06 1.48 E. India 2001 334 05:02 26.76 229.56 50.59 236.64 1.56 Washington 2001 334 19:26 13.62 13.15 49.55 10.42 1.45 Italy 2001 335 09:42 10.30 158.61 49.96 161.16 1.49 New Zealand 2001 335 23:44 26.62 307.31 49.72 300.35 1.53 Guyana no operations - superceded by another experiment 2001 337 04:12 26.54 239.15 49.35 244.97 1.52 California 2001 337 18:34 16.23 23.21 50.70 21.73 1.47 Greece 2001 338 08:50 13.10 168.67 50.40 173.06 1.46 New Zealand 2001 338 22:54 26.41 316.91 50.75 309.02 1.53 Brazil There is a receiver at the South Pole station programmed to receive the 130 and 380 kHz transmissions. RPI whistler mode team	Transmission Schedule The first transmission will be a VLF propagation to the ground experiment starting at 0728 UT on 11/21/01. The second will be a South Pole experiment with transmission starting at 0814 UT on 11/21/01 and continuing for eight minutes. The transmissions will occur in the same sequence every orbit, scheduled with respect to the closest approach to the South Pole and will end on UT 12/04. The last two experiments will be a transmission for VLF propagation to the ground starting at 2248 UT on 12/04/01 and a South Pole transmission starting at 2334 UT on 12/04/01 and continuing for eight minutes. One of the sets of experiments in the two weeks will not occur because of a previous scheduled and very infrequent opportunity for a propagation experiment from IMAGE/RPI to the WAVES instrument on another satellite, Wind, at 508 and 828 kHz which will happen from 1100 to 1600 UT on 12/02/01. That will supercede the operations near the second perigee on 12/02/01. The table below gives the transmission start times for the two sets of experiments. DAY# DATE TRANS START TIMES, UT SP VLF Notes 325 11/21 0814 0728 2228 2142 326 11/22 1242 1156 327 11/23 0256 0210 1710 1624 328 11/24 0724 0638 2138 2052 329 11/25 1152 1106 330 11/26 0206 0120 1620 1534 331 11/27 0634 0548 2047 2001 332 11/28 1101 1015 333 11/29 0115 0029 1529 1443 334 11/30 0543 0457 1956 1910 335 12/01 1010 0924 336 12/02 0024 2338 VLF start on 12/01 UT none none superceded by another experiment 337 12/03 0452 0406 1906 1820 338 12/04 0920 0834 2334 2248


Curators Dr. E. V. Bell, II, ed.bell@gsfc.nasa.gov, +1-301-286-1187 NSSDC, Mail Code 633, NASA Goddard Space Flight Center, Greenbelt, MD 20771 Dr. D. R. Williams dwilliam@nssdc.gsfc.nasa.gov, +1-301-286-1258 NSSDC, Mail Code 633, NASA Goddard Space Flight Center, Greenbelt, MD 20771 NASA Approval: J. L. Green, james.l.green@gsfc.nasa.gov Rev. 3.0.0, 21 November 2001