Kinetic-scale turbulence
Spectral breaks, anisotropy, compressibility, and electric-field structure in MMS and solar-wind data.
Space Plasma Physics
Mani K Chettri
PhD candidate · Department of Physics, Sikkim University
I am a final-year PhD candidate in Physics at Sikkim University, Gangtok, originally from Sikkim in Northeast India. I study how turbulent energy cascades to kinetic scales and is dissipated in collisionless space plasmas. My work combines high-resolution spacecraft observations with pseudospectral simulations of nonlinear plasma models, focusing on kinetic Alfvén waves in Earth's magnetosphere and the solar wind.
Expected PhD completion: First quarter of 2027
Available for postdoctoral appointments: From early 2027
Kinetic Alfvén WavesPlasma TurbulenceMMS ObservationsPseudospectral SimulationsSolar WindMagnetosphere
6
Peer-Reviewed Articles
5
Preprints
arXiv and SSRN
4
Spacecraft Missions
MMS, Wind, PSP, Aditya-L1
1
Open-Source Tool
Alfvenica
Selected paperJournal of Atmospheric and Solar-Terrestrial Physics · September 2026
MMS observations of kinetic Alfvén wave turbulence and steep kinetic-range spectra in the outer Plasma Sheet Boundary Layer
Chettri, M. K., Mukherjee, R., & Singh, H. D. (2026). Article 106920.
From MMS burst-mode data I measure a kinetic-range magnetic spectral slope of −3.48 ± 0.13, alongside KAW diagnostics and impulsive parallel electric fields. That slope is steeper than an undamped KAW cascade would give, which points to substantial energy removal at kinetic scales.
Research Focus
Nonlinear wave coupling
Pseudospectral studies of modified Zakharov and nonlinear Schrödinger frameworks for KAW coupling, density structuring, and spectral evolution.
Collisionless dissipation
Understanding how turbulent energy is removed from the cascade and transferred to particles in weakly collisional space plasmas.
Recent Updates
PublishedAugust 2026
Paper on KAW turbulence in the outer PSBL
Out now in the Journal of Atmospheric and Solar-Terrestrial Physics, September 2026 issue (Article 106920).
Workshop6–15 July 2026
13th Aditya-L1 Support Cell Workshop
Ten days of training on Aditya-L1 data products at ARIES, Nainital.
Poster29 June–3 July 2026
52nd EPS Conference on Plasma Physics, Edinburgh
Presented work on ponderomotive density-cavity generation through KAW–slow-mode coupling.
Education
2022–2027
PhD in Physics (expected Q1 2027)
Sikkim University, Gangtok
Thesis: Numerical Study of Nonlinear Plasma Phenomena in the Heliosphere
2020–22
MSc in Physics
Sikkim Manipal Institute of Technology
2016–19
BSc Physics (Honours)
Nar Bahadur Bhandari Degree College, Tadong
Postdoctoral positions and research collaborations
I expect to complete my PhD in the first quarter of 2027, and I am looking for a group working on kinetic-scale turbulence or wave–particle interactions, from either the observational or the simulation side. I am glad to discuss possible projects, collaborations, or joint fellowship applications.
Research
My research asks how energy moves from large magnetohydrodynamic scales into the kinetic range, and how it is dissipated once it gets there. I use spacecraft observations together with reduced nonlinear models and pseudospectral simulations to study kinetic Alfvén waves, density structuring, and wave–particle energy transfer in collisionless plasmas.
Core Research Themes
01 · Magnetosphere
KAW turbulence in boundary layers
Spectral evolution, electric-to-magnetic fluctuation ratios, magnetic compressibility, and parallel electric fields in the plasma sheet boundary layer and magnetosheath.
02 · Nonlinear dynamics
Wave coupling and density structuring
Modified Zakharov and NLSE-type descriptions of KAW coupling to ion-acoustic or slow-mode fluctuations, including ponderomotive density cavities and spectral redistribution.
03 · Solar wind
Turbulence across heliocentric regimes
Comparing numerical models against Wind and Parker Solar Probe measurements, and against Aditya-L1 data as it becomes available, to study beta dependence and kinetic-scale dissipation.
04 · Plasma instabilities
Relativistic and collisionless instabilities
Secondary work on Weibel and two-stream instabilities across astrophysical and laboratory plasma conditions.
05 · Magnetic reconnection
Energy conversion and particle energisation
How reconnection releases magnetic energy and energises particles, and how that activity connects to the kinetic-scale turbulence observed in the same magnetotail boundary regions.
06 · Solar activity
Flare modelling with Aditya-L1
Building X-ray light curves with GOES for event context, then fitting time-resolved spectra to follow how temperature, emission measure, and elemental abundances evolve through the rise, peak, and decay of a flare.
Selected Research Highlights
Published · 2026MMS · Outer PSBL
Steep kinetic-range KAW turbulence in the plasma sheet boundary layer
High-resolution MMS observations reveal a kinetic-range slope of −3.48 ± 0.13, low magnetic compressibility, enhanced electric-to-magnetic ratios, and impulsive parallel electric fields. Together these point to substantial collisionless energy removal, though they do not single out one damping channel.
Read the paper ↗Published · 2024Nonlinear simulation
Nonlinear coupling of KAWs and ion-acoustic waves
A modified Zakharov framework was used to study magnetic filamentation and compressive density structures under inner-heliospheric plasma conditions.
Publisher version ↗Published · 2026Broadband simulation
Ponderomotive density cavitation and inertial-range suppression
Numerical results explore how broadband sub-Alfvénic turbulence can produce density cavities and modify inertial-range power under plasma sheet boundary layer conditions.
DOI ↗Approach
Theory
Two-fluid descriptions, modified Zakharov systems, nonlinear Schrödinger formulations, and reduced kinetic effects.
Numerics
Fourier pseudospectral methods, 2/3 dealiasing, RK4 and split-step integration, and MPI-parallelised computation.
Observations
PySPEDAS-based multi-instrument workflows, spectral analysis, field-aligned decomposition, and cross-checks across validated frequency ranges.
Space Missions
Spacecraft measurements underpin most of my work. Each card states how far that mission has actually gone in my research, from published analysis through to training.
Primary published data source
MMS
Magnetospheric Multiscale mission
High-resolution burst-mode field and plasma observations are used to study KAW turbulence in Earth's outer plasma sheet boundary layer and high-β magnetosheath.
PSBLMagnetosheathKinetic spectraParallel electric fields
Related JASTP paper ↗Solar-wind studies
Wind
Solar wind near 1 AU
Wind observations provide a reference environment for solar-wind turbulence, beta-dependent spectral behaviour, and comparison with nonlinear simulation frameworks.
1 AU solar windSpectral analysisModel comparison
Inner-heliospheric context
Parker Solar Probe
Near-Sun plasma conditions
Parker Solar Probe data and plasma conditions are used to frame nonlinear KAW–ion-acoustic coupling and the evolution of turbulence closer to the Sun.
Inner heliosphereNear-Sun turbulenceNonlinear waves
Training and emerging analysis
Aditya-L1
India's solar observatory at L1
Participation in Aditya-L1 Support Cell workshops has provided hands-on training with ASPEX, PAPA, and MAG data products, supporting future solar-wind analysis.
ASPEXPAPAMAGSupport Cell training
Data-analysis workflow
01
Data selection
Event context, cadence, quality flags, and validated instrument ranges.
02
Pre-processing
Coordinate transforms, interpolation, field-aligned decomposition, and cross-instrument alignment.
03
Diagnostics
Power spectra, ratios, compressibility, phase relationships, and statistical tests.
04
Validation
Independent instruments, common frequency bands, uncertainties, and model comparison.
Peer-Reviewed Journal Articles
First Author · Journal · 2026Journal of Atmospheric and Solar-Terrestrial Physics
MMS observations of kinetic Alfvén wave turbulence and steep kinetic-range spectra in the outer Plasma Sheet Boundary Layer
Chettri, M. K., Mukherjee, R., & Singh, H. D. (2026). J. Atmos. Sol.-Terr. Phys., Article 106920.
A burst-mode MMS study of the outer PSBL reporting KAW turbulence, a steep kinetic-range spectral slope, and impulsive parallel electric fields.
MMSKAW TurbulenceOuter PSBLCollisionless DissipationSpectral Steepening
Journal · 2026Journal of Subatomic Particles and Cosmology
Inertial-Range Suppression and Ponderomotive Density Cavitation in Broadband Sub-Alfvénic Turbulence under Plasma Sheet Boundary Layer Conditions
Chettri, M. K., Shrivastav, V., Singh, B., Mukherjee, R., & Singh, H. D. (2026). J. Subat. Part. Cosmol., 100383.
PSBL TurbulencePonderomotive EffectsNLSE SimulationInertial-Range
Journal · 2026Journal of Subatomic Particles and Cosmology
Suppression of Two-Stream and Weibel Instabilities in Ultra-Relativistic Electron–Positron Plasma
Shrivastav, V., Chettri, M. K., Singh, H. D., Singh, B., & Mukherjee, R. (2026). J. Subat. Part. Cosmol., 100421.
Two-Stream InstabilityWeibel InstabilityUltra-relativisticElectron–Positron Plasma
Journal · 2026Contributions to Plasma Physics
Weibel Instability in Collisionless Plasmas across Astrophysical and Laboratory Shocks
Shrivastav, V., Chettri, M. K., Singh, H. D., Singh, B., & Mukherjee, R. (2026). Contrib. Plasma Phys., Early View.
Weibel InstabilityCollisionless ShocksAstrophysical Plasmas
Journal · 2026PANE Journal of Physics Education
How Big Is the Sun? A Measurement from India's Aditya-L1 Spacecraft
Mukherjee, R., Chettri, M. K., Shrivastav, V., Singh, B., & Singh, H. D. (2026). P. J. Phys. Edu., 1(1), 60–74.
Solar RadiusAditya-L1SUITPhysics Education
Journal · 2024Research in Astronomy and Astrophysics
Nonlinear coupling of kinetic Alfvén waves and ion acoustic waves in the inner heliosphere
Chettri, M. K., Shrivastav, V., Mukherjee, R., Gaur, N., Sharma, R., & Singh, H. D. (2024). Res. Astron. Astrophys., 24(10), 105009.
KAW–IAW CouplingInner HeliosphereNonlinear Dynamics
Preprints and Submitted Work
Preprint · 2026arXiv · Submitted to Advances in Space Research
Electromagnetic signatures of kinetic Alfvén wave turbulence at ion inertial scales in Earth's high-β magnetosheath
Chettri, M. K., Mukherjee, R., & Singh, H. D. (2026). arXiv:2605.25199.
KAW TurbulenceMagnetosheathMMSHigh-βIon Inertial Scale
arXiv:2605.25199 ↗
Preprint · 2026arXiv
Ion channel dynamics in temperature-dependent Weibel instability saturation
Shrivastav, V., Chettri, M. K., Singh, H. D., Singh, B., & Mukherjee, R. (2026). arXiv:2604.21875.
Weibel InstabilityIon ChannelsTemperature DependenceSaturation
arXiv:2604.21875 ↗
Preprint · 2026SSRN
A validated analysis workflow for near-Earth spacecraft plasma observations: methodology, quality controls, and systematic error assessment
Chettri, M. K., Shrivastav, V., Singh, B., Mukherjee, R., & Singh, H. D. (2026). SSRN 6394663.
PySPEDASMethodologyData QualityMMS
View on SSRN ↗
Preprint · 2025arXiv
Damped kinetic Alfvén waves in Earth's magnetosheath: numerical simulations and MMS observations
Chettri, M. K., Singh, H. D., Shrivastav, V., Singh, B., & Mukherjee, R. (2025). arXiv:2512.09828.
KAW DampingMagnetosheathMMSSimulation
Preprint · 2025arXiv
Suppression of two stream instability in relativistic electron-ion plasmas
Shrivastav, V., Chettri, M. K., Singh, H. D., & Mukherjee, R. (2025). arXiv:2508.14362.
Plasma InstabilitiesRelativistic PlasmasTwo-Stream
In Progress
- • Solar-wind KAW turbulence from Wind data, tested against the NLSE simulation framework
- • A software paper describing Alfvenica (formerly PLASMAform) (in preparation)
Methods & Tools
Most of my work rests on three things: a PySPEDAS-based pipeline for spacecraft data, pseudospectral codes for the nonlinear models, and MPI runs on the IUCAA cluster. Alfvenica (formerly PLASMAform) grew out of the same work.
Observations
Spacecraft Data Analysis
PySPEDAS-based data access, field-aligned coordinate systems, cadence matching, spectral and cross-spectral methods, uncertainty checks, and multi-instrument validation.
PySPEDASMMSSpectral analysis
Simulation
Nonlinear Plasma Models
Modified Zakharov and nonlinear Schrödinger frameworks solved with Fourier pseudospectral methods, 2/3 dealiasing, RK4, and split-step Fourier integration.
PythonFortranPseudospectral
Computing
High-Performance Computing
MPI-parallelised workflows using mpi4py and mpi4py-fft, with computational work carried out on IUCAA HPC resources.
MPImpi4pyIUCAA HPC
Open Source · 2026Browser-based research tool
Alfvenica (formerly PLASMAform)
A browser-based space-plasma toolkit, calculator, and formula reference that states its assumptions and checks its own numbers.
Alfvenica is a validated, unit-explicit browser toolkit for space and astrophysical plasma physics. It brings together a searchable calculator, formula-level physical interpretation, reproducible plotting, worked plasma states, assumptions and references, and an in-browser validation report.
Calculator
Unit-explicit formulas
Plots
CSV and SVG export
Examples
Worked plasma states
Validation
Tests and references
Space/SI/CGS unitsLocal browser calculationsPhysical assumptionsReproducible plotsDocumented limitations
Open Research Resources
GuideLinux & Windows
PySPEDAS Installation Guide
Step-by-step installation, environment setup, verification, and troubleshooting for PySPEDAS 2.x.
Download PDF ↗GuideMigration to v2.x
PySPEDAS Fix and Migration Guide
A practical reference for updating mission imports, get_data usage, standard script templates, and common error fixes.
Download PDF ↗Talks & Training
Conference presentations, workshops, and training, most recent first.
Presentations, Workshops & Training
Jul 2026
Workshop
13th Aditya-L1 Support Cell Workshop
ARIES, Nainital, India · 6–15 July 2026
Ten-day workshop on Aditya-L1 data products and their analysis.
Jun–Jul 2026
Poster
52nd EPS Conference on Plasma Physics (EPS-2026)
EICC, Edinburgh, United Kingdom · 29 June–3 July 2026
Poster presentation: Ponderomotive generation of density cavities from kinetic Alfvén wave–slow-mode coupling.
May 2026
Training
Elsevier Researcher Academy
Certificates of Excellence · Online
Modules on research ethics and authorship.
Feb 2026
Training
Training Programme on AI & ML in Space Exploration
India Space Academy · 23–28 February 2026 · Online
Six-day programme on machine-learning applications in space science.
Feb 2026
Oral
Trends in Science and Technology (TIST-2026)
Salesian College, Siliguri · 27–28 February 2026
Oral presentation: Damped Kinetic Alfvén Waves in Earth's Magnetosheath: Numerical Simulations and MMS Observations.
Jan 2026
Poster
5th Conference on Plasma Simulation (CPS-2026)
IPS Academy and IIT Indore, India
Poster on KAW turbulence simulations in the plasma sheet boundary layer with MMS comparison.
Dec 2025
Workshop
Aditya-L1 Support Cell Workshop
IIT Jammu, India · Organised by ISRO
Three-day workshop on solar wind data analysis using Aditya-L1 data products (ASPEX, PAPA, MAG) through ISSDC/PRADAN.
Dec 2025
Oral
XV PANE Conference 2025
Nagaland University, Lumami, India
Oral presentation: Turbulent Signatures of Kinetic Alfvén Waves in Earth's Plasma Sheet Boundary Layer.
Professional Memberships
2026–27
American Physical Society (APS)
Division of Plasma Physics
2026
European Geosciences Union (EGU)
Solar-Terrestrial Sciences (ST) Division
2026
European Physical Society (EPS)
Individual Member
Teaching
2019–20
Science Teacher
St. Mary's Convent School, West Sikkim
2017–19
Mathematics Tutor
Grace Academy, Gangtok
Leadership
2019
President, Convention on Climate Change
Namchi Degree College
2018
President, Physicist Meet
Manan Kendra, Gangtok
Contact
I am glad to hear from anyone about postdoctoral openings or collaborations, particularly on spacecraft data analysis and numerical plasma modelling.
Postdoctoral availability
Available from the first quarter of 2027. I am looking for heliophysics groups working on kinetic-scale turbulence, wave–particle interactions, or computational plasma physics.
Details
Address
Department of Physics
School of Physical Sciences
Sikkim University
6th Mile, Samdur, P.O. Tadong
Gangtok, Sikkim 737102, India
Supervisors
Dr. Hemam Dinesh Singh (NSUT, New Delhi)
Dr. Rupak Mukherjee (Sikkim University, IUCAA)