in Wikipedia I see eighteen discoveries by WIND but not that particular one...
Yes, I have not had a chance to update the list of Wind discoveries for quite a while but plan to do so soon.
...while the STEREO spacecraft had a cluster of instruments called "IMPACT" the Wikipedia article doesn't mention the detection of dust impacts...
The IMPACT instrument is part of a suite of instruments on STEREO but has nothing to do with dust particles. The discovery of dust detections by STEREO came from the WAVES instrument, specifically the time domain sampler (TDS) reciever. The TDS on STEREO produces 16,384 three component vector electric field measurements as a time series snapshot centered on the the peak signal amplitude.
How where these plasma clouds first noticed, and eventually attributed to dust impacts?
The following is an excerpt from Kellogg et al. [2016]:
At first attributed to interference, Michael Kaiser and Keith Goetz (unpublished STEREO Team meetings) began to explore the idea that the STEREO signals were due to dust impacts, similar to those investigated at Saturn [Gurnett et al., 1983; Aubier et al., 1983; Meyer-Vernet et al., 2009a]. This idea was pursued, especially by Meyer-Vernet et al. in several papers [2009a, 2009b]. The STEREO data were then extensively analyzed by Zaslavsky et al. [2012] and by Belheouane et al. [2012]. Debris simultaneous with signals on antennas has been observed with the optical imagers on STEREO [St. Cyr et al., 2009]. Interpretation of these waveforms seems now to be established.
To the best of my knowledge, the first electric field observations were in 1981 but were not properly interpreted until the 1983 papers by Gurnett et al. and Aubier et al.
Dust impacts have been observed by electric field probes on (in no particular order) Cassini [e.g., Kurth et al., 2006], Wind [e.g., Malaspina et al., 2014; Kellogg et al., 2016], STEREO [e.g., Meyer-Vernet et al., 2009], Voyager [e.g., Gurnett et al., 1983; Aubier et al., 1983], Vega [e.g., Laakso et al., 1989], Deep Space 1 [e.g., Tsurutani et al., 2004], and MAVEN [e.g., Andersson et al., 2015] spacecraft.
The Ulysses spacecraft has a dedicated dust detection instrument. It was this instrument that discovered interstellar dust (ISD) [Grun et al., 1993; Mann, 2010; Mann et al., 2010].
...but I'm wondering if there was a "hey, what the heck are these strange pulses - oh, that's what they are!" story I can read, or otherwise learn about...
The introduction by Kellogg et al. [2016] and the two Voyager papers by Gurnett et al. [1983] and Aubier et al. [1983] have some interesting comments on the original thoughts regarding these signals.
There were good reasons to think that the electric field signals were artificial. Below I show four characteristic examples of dust impacts (i.e., Types A-D) observed by the Wind spacecraft's WAVES TDS receiver:
and two characteristic examples instrument interference signals (i.e., Types E and F):
You can see that there are several similarities between the dust impact signals and the artificial instrument responses, which is why some of the original observations (e.g., those made in 1981) were interpreted as instrument interference.
Below I have listed several relevant references but note that this list is certanly not comprehensive and that there are dozens more. A good place to start would be to dig through the reference lists in Kellogg et al. [2016], Malaspina et al. [2014], and the two 2010 papers by I. Mann.
References
- Andersson, L., et al. "Dust observations at orbital altitudes surrounding Mars," Science 350, pp. 0398, doi:10.1126/science.aad0398, 2015.
- Aubier, M.G., N. Meyer-Vernet, and B.M. Pedersen "Shot noise from grain and particle impacts in Saturn's ring plane," Geophys. Res. Lett. 10, pp. 5-8, doi:10.1029/GL010i001p00005, 1983.
- Gr$\ddot{u}$n, E., et al. "Discovery of Jovian dust streams and interstellar grains by the ULYSSES spacecraft," Nature 362, pp. 428-430, doi:10.1038/362428a0, 1993.
- Gurnett, D.A., E. Grun, D. Gallagher, W.S. Kurth, and F.L. Scarf "Micron-sized particles detected near Saturn by the Voyager plasma wave instrument," Icarus 53, pp. 236-254, doi:10.1016/0019-1035(83)90145-8, 1983.
- Kellogg, P.J., K. Goetz, and S.J. Monson "Dust impact signals on the Wind spacecraft," J. Geophys. Res. 121(2), pp. 966-991, doi:10.1002/2015JA021124, 2016.
- Kurth, W.S., T.F. Averkamp, D.A. Gurnett, and Z. Wang "Cassini RPWS observations of dust in Saturn’s E Ring," Planet. Space Sci. 54, pp. 988-998, doi:10.1016/j.pss.2006.05.011, 2006.
- Laakso, H., R. Grard, A. Pedersen, and G. Schwehm "Impacts of large dust particles on the VEGA spacecraft," Adv. Space Res. 9, pp. 269-272, doi:10.1016/0273-1177(89)90273-1, 1989.
- Malaspina, D.M., et al., "Interplanetary and interstellar dust observed by the Wind/WAVES electric field instrument," Geophys. Res. Lett. 41, pp. 266-272, doi:10.1002/2013GL058786, 2014.
- Mann, I., et al. "Dust in the interplanetary medium," Plasma Phys. Control. Fusion 52, pp. 124012, doi:10.1088/0741-3335/52/12/124012, 2010.
- Mann, I. "Interstellar Dust in the Solar System," Annual Review of Astronomy and Astrophysics 48, pp. 173-203, doi:10.1146/annurev-astro-081309-130846, 2010.
- Meyer-Vernet, N., et al. "Dust detection by the Wave instrument on STEREO: Nanoparticles picked up by the solar wind?," Sol. Phys. 256, pp. 463-474, doi:10.1007/s11207-009-9349-2, 2009.
- Scarf, F.L., D.A. Gurnett, W.S. Kurth, and R.L. Poynter "Voyager plasma wave measurements at Saturn," J. Geophys. Res. 88, pp. 8971-8984, doi:10.1029/JA088iA11p08971, 1983.
- Tsurutani, B.T., et al. "Plasma clouds associated with Comet P/Borrelly dust impacts," Icarus 167, pp. 89-99, doi:10.1016/j.icarus.2003.08.021, 2004.
