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.
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.
Kinetic Alfvén WavesPlasma TurbulenceMMS ObservationsPseudospectral SimulationsSolar WindMagnetosphere
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
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
Wind/SWE measurements support a published comparison of Alfvénic and non-Alfvénic slow wind, proton anisotropy, compressive fluctuations, and parallel-mode marginal stability. Parker Solar Probe and Aditya-L1 provide further solar-wind context.
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.
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.
Recent Academic Activity
2–6 November 2026
European Space Weather Week 2026 · Florence, Italy
Poster presentation on MMS Observations of Kinetic Alfvén Wave Turbulence and Steep Kinetic-Range Spectra in the Outer Plasma Sheet Boundary Layer (virtual mode).
26 October – 6 November 2026
Plasma Turbulence Across Scales · ICTS-TIFR, Bengaluru, India
- Contributed talk: MMS observations of kinetic Alfvén-like fluctuations in the magnetosheath and plasma sheet boundary layer
- Poster presentation: Electromagnetic Signatures of Kinetic Alfvén Wave Turbulence at Ion Kinetic Scales in Earth's High-β Magnetosheath
5 October 2026
Advances in Space Research paper available online
MMS observations of kinetic Alfvén wave turbulence at ion inertial scales in Earth's high-β magnetosheath. Read the paper ↗
September 2026
JASTP paper on outer plasma sheet boundary layer turbulence
MMS observations of kinetic Alfvén wave turbulence and steep kinetic-range spectra, published in the Journal of Atmospheric and Solar-Terrestrial Physics. Read the paper ↗
29 June – 3 July 2026
52nd EPS Conference on Plasma Physics
Poster presentation in Edinburgh, United Kingdom: Ponderomotive generation of density cavities from kinetic Alfvén wave–slow-mode coupling.
Publications
Peer-reviewed journal articles, including papers available online, and preprints. Google Scholar ↗
Selected Publications
PUBLISHED ONLINE · 2026Advances in Space Research · 2026
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). Advances in Space Research. Available online 5 October 2026. In Press, Corrected Proof. arXiv:2605.25199.
MMS observations place the spectral break closer to the ion inertial scale than to the ion gyroradius in a high-β magnetosheath interval. Electromagnetic and propagation diagnostics support a quasi-perpendicular KAW-like interpretation.
MMSHigh-β MagnetosheathIon Inertial ScaleKAW-like Turbulence
PUBLISHED · 2026Journal of Atmospheric and Solar-Terrestrial Physics · 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). J. Atmos. Sol.-Terr. Phys., 286, 106920.
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.
MMSKAW TurbulenceOuter PSBLCollisionless DissipationSpectral Steepening
PUBLISHED · 2026Journal of Subatomic Particles and Cosmology · 2026
Alfvénicity and proximity to parallel-mode marginal stability in the slow solar wind
Chettri, M. K., Mukherjee, R., & Singh, H. D. (2026). J. Subat. Part. Cosmol., 6, 100522. Available online 18 September 2026.
Five years of Wind/SWE data show that, at matched low parallel proton beta, Alfvénic slow wind has lower normalized field-strength fluctuation amplitude and more often reaches the parallel-mode marginal-stability criterion. The association is consistent with a fluctuating-anisotropy interpretation but does not establish causation.
Wind/SWESlow Solar WindAlfvénicityProton AnisotropyVlasov Analysis
PUBLISHED · 2024Research in Astronomy and Astrophysics · 2024
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. P., & Singh, H. D. (2024). Res. Astron. Astrophys., 24(10), 105009.
A modified Zakharov framework was used to study magnetic filamentation and compressive density structures under inner-heliospheric plasma conditions.
KAW–IAW CouplingInner HeliosphereNonlinear Dynamics
Other Peer-Reviewed Journal Articles
PUBLISHED · 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., 5, 100383.
Numerical results explore how broadband sub-Alfvénic turbulence can produce density cavities and modify inertial-range power under plasma sheet boundary layer conditions.
PSBL TurbulencePonderomotive EffectsNLSE SimulationInertial-Range
PUBLISHED · 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., 6, 100421.
Two-Stream InstabilityWeibel InstabilityUltra-relativisticElectron–Positron Plasma
PUBLISHED · 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., e70147.
Weibel InstabilityCollisionless ShocksAstrophysical Plasmas
PUBLISHED · 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
PUBLISHED · 2026PANE Journal of Physics Education
A Tutorial for Sparse Identification of Nonlinear Dynamical System (SINDy) framework to discover governing equations from raw data
Singh, B., Chettri, M. K., Shrivastav, V., Singh, H. D., & Mukherjee, R. (2026). P. J. Phys. Edu., 1(1), 32–45.
SINDyDynamical SystemsData-Driven Methods
Preprints and Submitted Work
PREPRINT · 2026arXiv
Direct Four-Spacecraft Measurement of Reconnection Exhaust Thickness in the Solar Wind
Chettri, M. K., Mukherjee, R., & Singh, H. D. (2026). arXiv:2609.03088.
MMSSolar WindMagnetic Reconnection
arXiv:2609.03088 ↗
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)
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 ↗Published solar-wind study
Wind
Solar wind near 1 AU
Wind/SWE measurements support my study of Alfvénic slow wind, proton temperature anisotropy, parallel beta, compressive fluctuations, and parallel-mode marginal stability using Vlasov dispersion calculations.
Wind/SWESlow solar windAlfvénicityProton anisotropy
Related JSPC paper ↗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.
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, training, and seminars. Presentations and workshops are listed most recent first.
Presentations, Workshops & Training
Nov 2026
Poster
European Space Weather Week 2026 (ESWW 2026)
Florence, Italy · 2–6 November 2026
Poster Presentation (completed): MMS Observations of Kinetic Alfvén Wave Turbulence and Steep Kinetic-Range Spectra in the Outer Plasma Sheet Boundary Layer.
Conference website ↗Oct–Nov 2026
Talk & Poster
Plasma Turbulence Across Scales: Integrating Theory and Observations
International Centre for Theoretical Sciences (ICTS-TIFR), Bengaluru, India · 26 October – 6 November 2026
Attended the programme and contributed:
- Contributed Talk: MMS observations of kinetic Alfvén-like fluctuations in the magnetosheath and plasma sheet boundary layer
- Poster Presentation: Electromagnetic Signatures of Kinetic Alfvén Wave Turbulence at Ion Kinetic Scales in Earth's High-β Magnetosheath
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
12th 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.
Nov 2025
Oral
XV PANE Conference 2025
Nagaland University, Lumami, India · 18–19 November 2025
Oral presentation: Turbulent Signatures of Kinetic Alfvén Waves in Earth's Plasma Sheet Boundary Layer.
JPP Frontiers of Plasma Physics Colloquium
Online seminar series · Journal of Plasma Physics · Attended in 2026
- 7 MayA parallel-kinetic-perpendicular moment model for magnetised plasmas
- 14 MayValidating benign termination as a reactor-relevant RE mitigation technique on the JET and DIII-D tokamaks
- 18 JuneCan Machine Learning Discover Closure Relations in Plasma Physics?
- 20 AugustElectron flat-top distributions and their relation to electron energization in magnetic reconnection
- 27 AugustExhaust dynamics of pellet-fueled plasmas in the DIII-D tokamak
- 10 SeptemberCurrent sheet formation and steady-state reconnection under radiative cooling
- 17 SeptemberExtending the double adiabatic equations to the relativistic regime
- 1 OctoberComputing MHD Equilibria via relaxation: GPU performance, magnetic islands, and questions of convergence
- 15 OctoberNonlinear Interplay of Turbulence, Alfvénic Modes, and Energetic Particles in Burning Plasmas
Other Scientific Seminars
Department of Aeronautics · Online · Attended in 2026
- 13 MayTransitional regimes in incompressible wall-bounded shear flows
- 1 SeptemberPromoting Parsimonious Priors for Planning, Projections, and Physics
Education
2022–present
PhD in Physics
Sikkim University, Gangtok
Thesis: Kinetic and Nonlinear Plasma Processes in Space and Astrophysical Plasmas
2020–22
MSc in Physics
Sikkim Manipal Institute of Technology
2016–19
BSc Physics (Honours)
Nar Bahadur Bhandari Degree College, Tadong
Professional Memberships
2026–27
European Space Weather and Space Climate Association (E-SWAN)
Invited member · 20 October 2026 – 20 October 2027
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
Part-time Mathematics Tutor
Grace Academy, Gangtok
Leadership
2019
President, Convention on Climate Change
Namchi Degree College
2018
President, Physicist Meet
Manan Kendra, Gangtok
Research Collaboration
I welcome questions and research collaborations on spacecraft observations, plasma turbulence, nonlinear wave dynamics, and computational plasma physics.
Please get in touch if our research interests overlap or if you would like to discuss a specific project.
Contact
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)