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Unit-explicit scientific calculator
Space-plasma parameters, with assumptions visible.
Search a formula, enter the plasma state, and inspect the calculation, units, scope, and source in one place.
Reproducible visualisation
Scale ordering and parameter dependence.
The plots are evaluated directly from the same physics core used by the calculators. They show the implemented equations exactly at the sampled points; physical applicability remains limited by the assumptions of each model.
Reference plasma state
Choose a preset or enter the fixed state used by both plotting tools.
integer
mᵢ/mₚ
Ordering diagram
Characteristic-scale hierarchy
Logarithmic markers compare standard frequencies and spatial scales for the reference state. Their ordering may change with the selected plasma environment.
View numerical values
View numerical values
Controlled parameter sweep
Parameter-dependence explorer
Vary one input while all other state variables remain fixed. Up to three quantities from the same physical family share a common axis and unit.
View sampled data
Scientific use
These plots contain no smoothing, fitting, or interpolated physics. Curves connect direct evaluations of the implemented equations only for readability. A visually smooth trend does not establish model validity, identify a wave mode, or replace uncertainty analysis. Exported files record the displayed values and fixed state.
Worked examples
From a plasma state to the scales that matter.
These examples use illustrative parameter sets to show how the core quantities fit together. They are not reconstructions of specific published events.
How to use the examples
Open a state in the calculator, then review every input against the interval, instrument cadence, coordinate system, and species definition used in your analysis.
Numerical quality control
Validation report
The core is checked against standard NRL coefficients, exact definitions, and registry-wide smoke tests.
| Test | Computed | Reference | Relative error | Status |
|---|
Interpretation
Passing these tests confirms implementation consistency for the tested definitions. It does not turn reduced formulas, empirical fits, or simplified instability criteria into general kinetic solvers. Each calculator states its own scope.
About the project
A transparent formulary for space-plasma work.
Alfvenica is designed as a calculator, a formula reference, and a reproducibility aid—not as a substitute for kinetic dispersion codes or instrument-specific analysis pipelines.
Design principles
All calculations and plots run locally in the browser through a single SI physics core; no input values are transmitted. Units are converted only at the interface, while formula definitions, assumptions, sources, plot metrics, and tests remain separate from the page layout.
Unit conventions
Space uses cm⁻³, nT, eV, km s⁻¹, and km where practical. SI uses m⁻³, T, K, m s⁻¹, and m. CGS uses cm⁻³, G, eV, cm s⁻¹, and cm. Derived quantities that are conventionally reported in SI retain SI units when a reliable CGS analogue would be ambiguous.
Scientific basis
Fundamental constants follow the 2022 CODATA set. Foundational plasma coefficients are cross-checked against the 2023 NRL Plasma Formulary. Empirical anisotropy thresholds retain the model assumptions and fit domain of the cited paper.
Limitations
Single-ion, scalar-temperature, fluid, reduced two-fluid, and frozen-flow assumptions appear in several tools. Users should not apply a result outside the stated regime without an independent derivation or a more complete numerical model.
Reading characteristic scales
A gyrofrequency, inertial length, gyroradius, or threshold is usually an ordering scale rather than a sharp universal boundary. Physical interpretation should compare several independent scales and retain uncertainty in density, temperature, field, flow, geometry, and species definition.
Observational interpretation
Spacecraft-frame frequencies, E/B ratios, current densities, and crossing thicknesses depend on frame choice, cadence, coordinate systems, and geometry. Alfvenica therefore presents them as transparent diagnostics to be combined with instrument validation and event context.
Suggested citation
Chettri, M. K. (2026). Alfvenica: Interactive Space Plasma Toolkit. mkchettri.in/alfvenica.
This release separates the physics engine, formula registry, validation suite, interface logic, and visual design to reduce scientific drift and simplify maintenance.