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.

View publications Latest paper ↗ Download CV ↗

Kinetic Alfvén WavesPlasma TurbulenceMMS ObservationsPseudospectral SimulationsSolar WindMagnetosphere

Published Articles

Accepted / In Press

Preprints

Spacecraft Missions

MMS, Wind, PSP, Aditya-L1

Selected Publications

All publications →

ACCEPTED · 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). Accepted for publication in Advances in Space Research. 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.

arXiv:2605.25199 ↗

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.

DOI: 10.1016/j.jastp.2026.106920 ↗ScienceDirect ↗arXiv ↗

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.

At matched low parallel proton beta, Alfvénic slow wind shows lower normalized field-strength fluctuation amplitude and more frequent approach to the parallel-mode marginal-stability criterion. The association does not establish causation.

DOI: 10.1016/j.jspc.2026.100522 ↗arXiv:2609.17671 ↗

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.

DOI: 10.1088/1674-4527/ad76ee ↗

Recent Academic Activity

Talks & Training →

Accepted · 2026

High-β magnetosheath KAW study

Accepted by Advances in Space Research; the preprint ↗ is available.

PublishedAvailable online 18 September 2026

Alfvénicity and marginal stability in the slow solar wind

A Wind/SWE study in the Journal of Subatomic Particles and Cosmology. Read the paper ↗

Workshop6–15 July 2026

13th Aditya-L1 Support Cell Workshop

Ten-day workshop on Aditya-L1 data products and their analysis at ARIES, Nainital, India.

Poster29 June–3 July 2026

52nd EPS Conference on Plasma Physics (EPS-2026)

Poster presentation: Ponderomotive generation of density cavities from kinetic Alfvén wave–slow-mode coupling.

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

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.

Publications

8 published journal articles · 1 accepted / in press · 5 preprints · Google Scholar ↗

Peer-Reviewed Journal Articles

ACCEPTED · 2026Advances 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). Accepted for publication in Advances in Space Research. arXiv:2605.25199.

MMSHigh-β MagnetosheathIon Inertial ScaleKAW-like Turbulence

arXiv:2605.25199 ↗

PUBLISHED · 2026Journal of Subatomic Particles and Cosmology

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

DOI: 10.1016/j.jspc.2026.100522 ↗arXiv:2609.17671 ↗

PUBLISHED · 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., 286, 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

DOI: 10.1016/j.jastp.2026.106920 ↗ScienceDirect ↗arXiv ↗

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

DOI: 10.1016/j.jspc.2026.100383 ↗ arXiv:2603.14436 ↗

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

DOI: 10.1016/j.jspc.2026.100421 ↗ ScienceDirect ↗

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

DOI: 10.1002/ctpp.70147 ↗

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

View Article ↗

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

View Article ↗

PUBLISHED · 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. P., & Singh, H. D. (2024). Res. Astron. Astrophys., 24(10), 105009.

KAW–IAW CouplingInner HeliosphereNonlinear Dynamics

DOI: 10.1088/1674-4527/ad76ee ↗

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

arXiv:2512.09828 ↗

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

arXiv:2508.14362 ↗

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

Data selection

Event context, cadence, quality flags, and validated instrument ranges.

Pre-processing

Coordinate transforms, interpolation, field-aligned decomposition, and cross-instrument alignment.

Diagnostics

Power spectra, ratios, compressibility, phase relationships, and statistical tests.

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

Launch Alfvenica ↗GitHub ↗

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

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

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

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

Part-time Mathematics Tutor

Grace Academy, Gangtok

Leadership

2019

President, Convention on Climate Change

Namchi Degree College

2018

President, Physicist Meet

Manan Kendra, Gangtok

Education

Full CV ↗

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

Contact

I welcome questions and research collaborations on spacecraft observations, plasma turbulence, nonlinear wave dynamics, and computational plasma physics.

Research collaboration

Please get in touch if our research interests overlap or if you would like to discuss a specific project.

Details

mkchettri8@gmail.com

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)

Profiles

Google Scholar

Publications and citations

ORCID

0009-0000-1368-9263

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Research updates