Day Fourteen - Data afterglow and evening
Yesterday (Monday, Day 14) was a very succesful run for my two experiments: PAMS (Pulsed Absorption in the Morning Sector) and DLETE (D - Layer Electron Temperature Enhancements).
During the earlier PAMS run we had some very nice precipitation effects that were distinctly quai-periodic, including potential drift echoes, which is another of my interests. The DLETE run is always harder to measure since we are interested not in the electron density, but rather in measuring any perceptable effects on the electron temperature. Te is notoriously difficult to measure in the D-Layer with incoherent scatter techniques. In fact, for difficult, read impossible. The closest thing we can get is to measure the spectral width of the returned signal; this is partly controlled by the electron temperature. By using the heater to pump in an on/off cycle we can compare the change in width on a statistical basis. That is the plan, anyway. However today we had a more immediate indicator that our heating was having an effect. As I reported, some PMWE appeared. It did disappear after a while but then cam back and it looks as if we might have succeeded in modulating it. For the last half hour or so we switched to a 1 minute on/off cycle and saw distinct changes in the returned power at the same frequency. There were other factors that made this very exciting as well. You can see the results on our EISCAT results page along with results from the FACE experiment runs.
Although cloudy last night Andrew ran the FACE experiment, this time using the arc1 modulation. However the data from the remotes was incredibly poor, even for similar levels of electron density. Andrew is working on his Plasma Line experiment but due to some possible changes in the operating system (we don't know what) it would not work. Brett Isham is having similar problems. The UHF started acting up towards the end of the run and so with a few minutes to go until teh scheduled stop time Andrew called a halt when yet another crow bar took the system down.
One thing that I have learned on this campaign is that in terms of steady reliabilty, the VHF surpasses the UHF. However the VHF is severely limited in pointing direction and when it has had faults they always seem to be big, hard to repair ones. It may go offline less frequently, but if we relied on just it we would probably be offline for long periods.
During the earlier PAMS run we had some very nice precipitation effects that were distinctly quai-periodic, including potential drift echoes, which is another of my interests. The DLETE run is always harder to measure since we are interested not in the electron density, but rather in measuring any perceptable effects on the electron temperature. Te is notoriously difficult to measure in the D-Layer with incoherent scatter techniques. In fact, for difficult, read impossible. The closest thing we can get is to measure the spectral width of the returned signal; this is partly controlled by the electron temperature. By using the heater to pump in an on/off cycle we can compare the change in width on a statistical basis. That is the plan, anyway. However today we had a more immediate indicator that our heating was having an effect. As I reported, some PMWE appeared. It did disappear after a while but then cam back and it looks as if we might have succeeded in modulating it. For the last half hour or so we switched to a 1 minute on/off cycle and saw distinct changes in the returned power at the same frequency. There were other factors that made this very exciting as well. You can see the results on our EISCAT results page along with results from the FACE experiment runs.
Although cloudy last night Andrew ran the FACE experiment, this time using the arc1 modulation. However the data from the remotes was incredibly poor, even for similar levels of electron density. Andrew is working on his Plasma Line experiment but due to some possible changes in the operating system (we don't know what) it would not work. Brett Isham is having similar problems. The UHF started acting up towards the end of the run and so with a few minutes to go until teh scheduled stop time Andrew called a halt when yet another crow bar took the system down.
One thing that I have learned on this campaign is that in terms of steady reliabilty, the VHF surpasses the UHF. However the VHF is severely limited in pointing direction and when it has had faults they always seem to be big, hard to repair ones. It may go offline less frequently, but if we relied on just it we would probably be offline for long periods.
posted by Kav at 7:30 pm
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