Multi-Needle Langmuir probe (mNLP) data on the Investigation of Cusp Irregularities (ICI) 4 sounding rocket

Documentation for file: ICI4_mNLP_01112021.mat <strong>The mNLP system on ICI-4</strong> The mNLP system on ICI-4 consisted of four cylindrical Langmuir probes with a diameter of 0.51 mm and a length of 25 mm [1,2]. The instruments allowed for current measurements at a sampling rate of 8680.5 Hz. The mNLP data included in the file are 1) the raw currents (‘I_mnlp’) in which spikes have been removed using a median filter over ten data points, and 2) the “filtered currents” (‘I_mnlp_filt’). For the latter, the spin of the payload and the three first harmonics were removed using a band-pass filter [1,2]. Additionally, components with frequencies larger than 1kHz were also removed. <strong>Variables:</strong> Variable name Units Description/Comment time_noNans seconds Time of flight since launch. Alt Km Altitude of the payload. I_mnlp Ampere Currents obtained by the four cylindrical Langmuir probes. The 1^st-4^th columns contain the currents obtained by the probes with bias voltages of 3V, 4.5V, 6V, and 7.5 V, respectively. The data was filtered using a median filter over ten data points. I_mnlp_filt Ampere Same as I_mnlp with additional filtering of currents using band-pass filters [1,2]. <strong>Acknowledgement</strong> The mNLP experiment and the ICI-4 campaign were funded through the Research Council of Norway. Thanks to Lasse Clausen, Espen Trondsen, Jøran I. Moen, David Michael Bang-Hauge, Bjørn Lybekk, and the Mechanical Workshop at the University of Oslo, Norway. <br> 1. Bekkeng, T. A., K. S. Jacobsen, J. K. Bekkeng, A. Pedersen, T. Lindem, J.‐P. Lebreton, and J. I. Moen (2010), Design of a multi‐needle Langmuir probe system, Meas. Sci. Technol., 21, 085,903, doi:10.1088/0957‐0233/21/8/085903 2. Jacobsen, K. S., Pedersen, A., Moen, J. I., &amp; Bekkeng, T. A. (2010), A new Langmuir probe concept for rapid sampling of space plasma electron density. Measurement Science and Technology, 21(8), https://doi.org/10.1088/0957‐0233/21/8/085902