Needle-like structures discovered on positively charged lightning branches


Lightning is a dangerous yet poorly understood natural phenomenon. Lightning forms a network of plasma channels propagating away from the initiation point with both positively and negatively charged ends—called positive and negative leaders1. Negative leaders propagate in discrete steps, emitting copious radio pulses in the 30–300-megahertz frequency band2,3,4,5,6,7,8 that can be remotely sensed and imaged with high spatial and temporal resolution9,10,11. Positive leaders propagate more continuously and thus emit very little high-frequency radiation12. Radio emission from positive leaders has nevertheless been mapped13,14,15, and exhibits a pattern that is different from that of negative leaders11,12,13,16,17. Furthermore, it has been inferred that positive leaders can become transiently disconnected from negative leaders9,12,16,18,19,20, which may lead to current pulses that both reconnect positive leaders to negative leaders11,16,17,20,21,22 and cause multiple cloud-to-ground lightning events1. The disconnection process is thought to be due to negative differential resistance18, but this does not explain why the disconnections form primarily on positive leaders22, or why the current in cloud-to-ground lightning never goes to zero23. Indeed, it is still not understood how positive leaders emit radio-frequency radiation or why they behave differently from negative leaders. Here we report three-dimensional radio interferometric observations of lightning over the Netherlands with unprecedented spatiotemporal resolution. We find small plasma structures—which we call ‘needles’—that are the dominant source of radio emission from the positive leaders. These structures appear to drain charge from the leader, and are probably the reason why positive leaders disconnect from negative ones, and why cloud-to-ground lightning connects to the ground multiple times.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Map of the 2017 flash.
Fig. 2: Expanded sections of Fig. 1, with a positive leader on the left and a negative leader on the right.
Fig. 3: A region around the structure labelled N4 in Fig. 2.
Fig. 4: A portion of a positive leader, in light of the behaviour of needles.

Data availability

To obtain the data, readers should submit a support request to the radio observatory via the ASTRON website ( The 2016 flash was from project LC6_003, observation L526419, time stamp D20160712T173455.100Z. The 2017 flash was from LC8 commissioning data, observation L612746, time stamp D20170929T202255.000Z.

Code availability

The data was processed with software archived at, version 2018.11.8.


  1. 1.

    Dwyer, J. R. & Uman, M. A. The physics of lightning. Phys. Rep. 534, 147–241 (2014).

    CAS  ADS  MathSciNet  Article  Google Scholar 

  2. 2.

    Chen, M. et al. Spatial and temporal properties of optical radiation produced by stepped leaders. J. Geophys. Res. D 104, 27573–27584 (1999).

    ADS  Article  Google Scholar 

  3. 3.

    Hill, J. D., Uman, M. A. & Jordan, D. M. High-speed video observations of a lightning stepped leader. J. Geophys. Res. D 116, D16117 (2011).

    ADS  Article  Google Scholar 

  4. 4.

    Edens, H. E., Eack, K. B., Rison, W. & Hunyady, S. J. Photographic observations of streamers and steps in a cloud-to-air negative leader. Geophys. Res. Lett. 41, 1336–1342 (2014).

    ADS  Article  Google Scholar 

  5. 5.

    Biagi, C. J., Uman, M. A., Hill, J. D. & Jordan, D. M. Negative leader step mechanisms observed in altitude triggered lightning. J. Geophys. Res. D 119, 8160–8168 (2014).

    ADS  Google Scholar 

  6. 6.

    Lyu, F., Cummer, S. A., Lu, G., Zhou, X. & Weinert, J. Imaging lightning intracloud initial stepped leaders by low-frequency interferometric lightning mapping array. Geophys. Res. Lett. 43, 5516–5523 (2016).

    ADS  Article  Google Scholar 

  7. 7.

    Qi, Q. et al. High-speed video observations of the fine structure of a natural negative stepped leader at close distance. Atmos. Res. 178–179, 260–267 (2016).

    Article  Google Scholar 

  8. 8.

    Jiang, R. et al. Channel branching and zigzagging in negative cloud-to-ground lightning. Sci. Rep. 7, 3457 (2017).

    ADS  Article  Google Scholar 

  9. 9.

    Rison, W., Thomas, R. J., Krehbiel, P. R., Hamlin, T. & Harlin, J. A GPS-based three-dimensional lightning mapping system: initial observations in central New Mexico. Geophys. Res. Lett. 26, 3573–3576 (1999).

    ADS  Article  Google Scholar 

  10. 10.

    Thomas, R. J. et al. Accuracy of the lightning mapping array. J. Geophys. Res. D Atmospheres 109, D14207 (2004).

    ADS  Article  Google Scholar 

  11. 11.

    Stock, M. G. et al. Continuous broadband digital interferometry of lightning using a generalized cross-correlation algorithm. J. Geophys. Res. D 119, 3134–3165 (2014).

    ADS  Article  Google Scholar 

  12. 12.

    Shao, X. M. & Krehbiel, P. R. The spatial and temporal development of intracloud lightning. J. Geophys. Res. D 101, 26641–26668 (1996).

    ADS  Article  Google Scholar 

  13. 13.

    Shao, X. M., Rhodes, C. T. & Holden, D. N. RF radiation observations of positive cloud-to-ground flashes. J. Geophys. Res. D 104, 9601–9608 (1999).

    ADS  Article  Google Scholar 

  14. 14.

    Yoshida, S. et al. Three-dimensional imaging of upward positive leaders in triggered lightning using VHF broadband digital interferometers. Geophys. Res. Lett. 37, L05805 (2010).

    ADS  Article  Google Scholar 

  15. 15.

    Dong, W., Liu, X., Yu, Y. & Zhang, Y. Broadband interferometer observations of a triggered lightning. Chin. Sci. Bull. 46, 1561–1565 (2001).

    Article  Google Scholar 

  16. 16.

    Shao, X. M., Krehbiel, P. R., Thomas, R. J. & Rison, W. Radio interferometric observations of cloud-to-ground lightning phenomena in florida. J. Geophys. Res. D 100, 2749–2783 (1995).

    ADS  Article  Google Scholar 

  17. 17.

    Edens, H. E. et al. VHF lightning mapping observations of a triggered lightning flash. Geophys. Res. Lett. 39, L19807 (2012).

    ADS  Article  Google Scholar 

  18. 18.

    Heckman, S. Why Does a Lightning Flash Have Multiple Strokes? PhD thesis, Massachusetts Institute of Technology. (1992).

  19. 19.

    Akita, M. et al. What occurs in K process of cloud flashes? J. Geophys. Res. D 115, D07106 (2010).

    ADS  Article  Google Scholar 

  20. 20.

    Mazur, V. The physical concept of recoil leader formation. J. Electrost. 82, 79–87 (2016).

    Article  Google Scholar 

  21. 21.

    Mazur, V. Triggered lightning strikes to aircraft and natural intracloud discharges. J. Geophys. Res. D 94, 3311–3325 (1989).

    ADS  Article  Google Scholar 

  22. 22.

    Mazur, V. Physical processes during development of lightning flashes. C. R. Phys. 3, 1393–1409 (2002).

    CAS  ADS  Article  Google Scholar 

  23. 23.

    Ngin, T. et al. Does the lightning current go to zero between ground strokes? Is there a current “cutoff”? Geophys. Res. Lett. 41, 3266–3273 (2014).

    ADS  Article  Google Scholar 

  24. 24.

    Norden, M. & Bregman, D. J. in 9th International Symposium on Electromagnetic Compatibility Joint with the 20th International Wroclaw Symposium on Electromagnetic Compatibility (EMC EUROPE 2010) 569–575, (2010).

  25. 25.

    van Haarlem, M. P. et al. LOFAR: The LOw-Frequency ARray. Astron. Astrophys. 556, A2 (2013).

    Article  Google Scholar 

  26. 26.

    Behnke, S. A., Thomas, R. J., Edens, H. E., Krehbiel, P. R. & Rison, W. The 2010 eruption of Eyjafjallajökull: lightning and plume charge structure. J. Geophys. Res. D 119, 833–859 (2014).

    ADS  Google Scholar 

  27. 27.

    Becerra, M. & Cooray, V. A self-consistent upward leader propagation model. J. Phys. D 39, 3708–3715 (2006).

    CAS  ADS  Article  Google Scholar 

  28. 28.

    Wang, Z. et al. High-speed video observation of stepwise propagation of a natural upward positive leader. J. Geophys. Res. D 121, 14,307–14,315 (2016).

    Google Scholar 

  29. 29.

    Malan, D. J. & Schonland, B. F. J. The electrical processes in the intervals between the strokes of a lightning discharge. Proc. R. Soc. Lond. A 206, 145–163 (1951).

    ADS  Article  Google Scholar 

  30. 30.

    Cooray, V. & Arevalo, L. Modeling the stepping process of negative lightning stepped leaders. Atmosphere 8, 245 (2017).

    ADS  Article  Google Scholar 

Download references


The LOFAR cosmic ray key science project acknowledges funding from an Advanced Grant of the European Research Council (FP/2007–2013)/ERC Grant Agreement number 227610. The project has also received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement number 640130). We furthermore acknowledge financial support from FOM (FOM-project 12PR304). A.N. is supported by the DFG (research fellowship NE 2031/2-1). T.W. is supported by the DFG (research fellowship NE WI 4946/1-1). This paper is based (in part) on data obtained with the International LOFAR Telescope (ILT) under project code LC6_003. LOFAR25 is the Low Frequency Array designed and constructed by ASTRON. It has observing, data processing and data storage facilities in several countries, that are owned by various parties (each with their own funding sources), and that are collectively operated by the ILT foundation under a joint scientific policy. The ILT resources have benefited from the following recent major funding sources: CNRS-INSU, Observatoire de Paris and Université d’Orléans, France; BMBF, MIWF-NRW, MPG, Germany; Science Foundation Ireland (SFI), Department of Business, Enterprise and Innovation (DBEI), Ireland; NWO, The Netherlands; The Science and Technology Facilities Council, UK; Ministry of Science and Higher Education, Poland.

Reviewer information

Nature thanks E. Williams and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Author information




B.M.H. and O.S. wrote the manuscript, developed the imaging technique and analysed the results. T.N.G.T., S.B., S.t.V., A.B., A.C., H.F., J.R.H., T.H., P.M., K.M., A.N., J.P.R., L.R., P.S. and T.W. are members of the LOFAR cosmic-ray key science project, and contributed to the acquisition, calibration and analysis of the LOFAR data. J.A., I.M.A., M.J.B., R.B., J.W.B., W.N.B., M.B., H.R.B., B.C., R.A.F., E.d.G., S.D., J.E., M.A.G., J.M.G., A.W.G., M.P.v.H., J.W.T.H., M.H., A.J.v.d.H., M.I., L.V.E.K., A.K., P.M., M.J.N., H.P., M.P.-P., V.N.P., R. Pekal, R. Pizzo W.R., H.R., H.J.A.R., A.R., D.J.S., A.S., J.S., O.S., M.S., M.T., M.C.T., A.v.A., R.A.M.J.W., R.J.v.W., O.W., P. Zarka and P. Zucca are members of the LOFAR Builders’s List, and contributed to these results through their efforts in the construction and commissioning of the LOFAR telescope. J.D. contributed through interpretation of the results. All authors approved the final version of the manuscript.

Corresponding authors

Correspondence to B. M. Hare or O. Scholten.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

This is a single document that includes significant additional information on our work. Including: description of our imaging technique, additional information about the 2016 and 2017 lightning flashes, additional needles that were imaged in the 2016 and 2017 flashes, additional hypothesis, discussions on the potential for optical observations of needles, and a simple location error analysis.

Video 1 Lightning: complete rotating

A 3D animation of the 2017 flash.

Video 2 Lightning detail: negative leader

A close-up animation of a negative leader in the 2017 flash.

Video 3 Lightning detail: needle

A close-up animation of a segment of positive leader, with needle N4 shown in red.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Hare, B.M., Scholten, O., Dwyer, J. et al. Needle-like structures discovered on positively charged lightning branches. Nature 568, 360–363 (2019).

Download citation

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing