Development of Electric Field-Controlled Open-System
Ionic Thruster
Shaik Aadil Iftikhaar
*
Pritee Parwekar and Md. Akhtar Khan
School of Technology, GITAM University, GITAM Deemed to be University, Hyderabad, Telangana, 502329, India
*Email: ashaik39@gitam.in (A. I. Shaik)
Abstract
This study presents the development of an open-system ionic thruster designed for silent and efficient propulsion
under atmospheric conditions. The thruster operates by generating a high-voltage corona discharge that ionizes a
working medium, either ambient air or a noble gas such as argon, and accelerates the resulting ions using a controlled
electrostatic field. The thrust is produced by the momentum transfer of these ions as they are expelled from the
system. A key focus of the design is the geometry of the negative (collector) electrode, which is shaped to manipulate
the local electric field and maximize ion acceleration while minimizing energy loss and ion recombination. The
proposed system offers a mechanically simple, scalable and modular solution without moving parts, making it ideal
for applications requiring silent operation and precise thrust control, such as unmanned aerial vehicles, near-space
platforms, and experimental aerospace propulsion systems.
Keywords: Silent; No moving parts; Open system; Field manipulation; Corrona discharge; Precise thrust; Modular.
1. Introduction
Ionic propulsion is an electrostatic method of thrust generation that uses electric fields to accelerate charged particles.
Unlike conventional propulsion systems with moving parts and combustion, ionic thrusters operate silently by ionizing
a working medium and directing the ions to produce thrust. The principle involves generating a corona discharge
between two electrodes. This discharge ionizes air or gas molecules, typically forming positive ions that are then
accelerated by an electric field. Fig. 4 demonstrates an early prototype implementation of this principle, showing the
fundamental electrode configuration used for ion acceleration.
Although ionic propulsion has been primarily used in space applications under vacuum conditions, recent studies have
demonstrated its feasibility in atmospheric environments. However, atmospheric operation presents challenges such
as increased ion recombination, energy losses, and reduced efficiency.
This study focuses on developing an open-system ionic thruster that operates in ambient air. The final optimized
designs, shown in Figs. 1 and 2, represent the culmination of iterative geometric refinements aimed at maximizing
thrust efficiency while maintaining silent operation.
1.1 Related work – technical comparative analysis
1.1.1 MIT ionic wind plane – Electro-aerodynamic Propulsion (EAD)
The MIT EAD prototype demonstrates a solid-state propulsion system that utilizes high-voltage (20–40 kV) corona
discharge to ionize air molecules, primarily N
2
+
and O
2
+
. The ions are accelerated towards a downstream collector
electrode, and their momentum is transferred to neutral air molecules through ion-neutral collisions. This produces a
net thrust commonly referred to as ionic wind. Notably, this process occurs in weakly ionized air at atmospheric
pressure without forming plasma.
[1]
Fig. 1: Iterated model with optimised electrode.
It features a completely solid-state and silent design with no moving parts, and it operates in ambient air without
requiring onboard propellant. However, its performance scales poorly with altitude due to reduced atmospheric density.
In contrast, our proposed open-system design (Fig. 1 and Fig. 2) addresses this limitation through optimized electrode
geometry that maintains efficiency across varying atmospheric conditions.
Fig. 2: Iterated model with optimise electrode.
Applications include low-altitude drones, experimental UAVs, and lightweight surveillance systems. The prototype
achieved a thrust-to-power ratio of approximately 0.6 mN/W, with a flight duration of around 12 seconds over 60
meters.
[1]
The prototype achieved a thrust-to-power ratio of approximately 0.6 mN/W. Our experimental setup, shown
in Fig. 3, demonstrates comparable thrust generation capabilities.
Fig. 3: Experimental prototype showing thrust in grams.
1.1.2 NASA Hall Effect Thruster (HET)
The Hall Effect Thruster employed by NASA functions by trapping electrons in a radial magnetic field, which results
in a Hall current that ionizes xenon propellant. The generated plasma is accelerated axially by an electric field,
producing thrust via the Lorentz force.
[2]
The system is efficient, using either permanent magnets or electromagnets to optimize the field configuration. It
performs optimally in vacuum conditions, making it suitable for deep space missions such as Psyche and DART, as
well as satellite station-keeping in geostationary and low Earth orbit.
Typical performance includes a specific impulse between 1,600–2,700 seconds and an efficiency of 50–60%, with
thrust outputs ranging from 40–200 mN depending on the model.
[2,3]
1.1.3 ISRO Gridded Ion Thruster (XIPS-Type)
ISRO’s ion thruster is based on a xenon ion propulsion system similar to the XIPS architecture. It ionizes xenon gas
using a hot filament cathode inside a cylindrical discharge chamber. The ions are extracted and accelerated through
multiple electrostatic grid stages, while a downstream neutralizer ensures charge balance.
[4]
The design is tailored for geostationary satellite station-keeping and offers long operational life exceeding 10,000
hours. It has been implemented in the GSAT satellite series and evaluated for interplanetary mission applications.
The thruster exhibits a specific impulse of around 3,000 seconds, a thrust of 25–35 mN, and an efficiency of
approximately 60%.
[4]
1.1.4 Busek Co. – BHT series hall effect thrusters
The BHT series from Busek Co. follows the traditional Hall-effect mechanism, using a radial magnetic field within an
annular discharge channel. Innovations include boron nitride ceramic insulators, scalable chamber architecture, and
power adaptability, allowing deployment across different spacecraft classes.
[5]
These thrusters have flown on CubeSats (e.g., BHT-200) and large spacecraft platforms (e.g., BHT-6000), including
missions such as STPSat-4 and AFRL programs. Applications span orbital station-keeping, interplanetary probes, and
broadband satellite constellations like OneWeb.
For instance, the BHT-6000 model delivers a thrust of 270–340 mN with a power input of 6 kW and a specific impulse
up to 2,300 seconds.
[5,6]
1.1.5 Aerojet Rocketdyne – AEPS (Advanced Electric Propulsion System)
AEPS utilizes radio-frequency (RF) excitation to generate plasma in a cylindrical chamber, followed by ion
acceleration through multi-stage electrostatic grids. Beam neutralization is achieved using a cathode at the exit plane.
The system is designed for high-power deep-space missions.
[7]
It supports high voltage grids (6–8 kV) and includes redundant control electronics for reliability in long-duration
missions. AEPS has been selected for use in NASA’s Artemis and Lunar Gateway programs.
Performance-wise, the system delivers thrust around 200–250 mN, with a power requirement of approximately 12–13
kW and a specific impulse near 3,400 seconds.
[7,8]
1.1.6 Frore Systems – AirJet® solid-state ionic cooling
Frore Systems’ AirJet® technology applies ionic wind principles to the domain of thermal management. It uses
MEMS-based high-voltage drivers that ionize ambient air via corona discharge. The ions are driven across narrow
electrode gaps to produce airflow by electrohydrodynamic drift, eliminating the need for mechanical fans.
[9]
The system operates at high-frequency field oscillations (20–40 kHz) and is exceptionally thin (less than 3 mm),
making it suitable for ultra-compact electronic devices. Applications include passive or hybrid cooling in consumer
electronics, such as high-performance laptops, GPUs, and CPUs.
Performance includes up to 5.25 CFM airflow, around 1750 Pa static pressure, and a low noise level of 21 dBA,
offering near-silent cooling performance.
[9,10]
1.2 Research gap
Despite the advancement of ionic propulsion systems, there are several unresolved challenges that hinder their broader
adoption and performance scalability.A primary concern is scalability. High-power Hall effect thrusters, such as
NASA’s 457M v2, display a nonlinear decrease in efficiency at higher power levels. The thrust-to-power ratio drops
from 76.4 mN/kW at low input power to just 46.1 mN/kW at 50 kW, indicating nonlinear scaling inefficiencies. The
modular architecture demonstrated in Fig. 1 and 2 addresses this limitation by enabling linear thrust scaling through
geometric extension rather than power increase. On the other end of the spectrum, miniaturization efforts for CubeSats
and small satellites face limitations such as plasma confinement losses and rapid electrode erosion. These arise because
of reduced mean free paths and enhanced wall interactions in microdischarge regimes, making effective downscaling
a difficult engineering task.
Propellant limitations also pose major constraints. Xenon, the most commonly used propellant, is both expensive and
logistically complex. Its price ranges from $5,000 to $12,000 per kilogram, and it must be stored under high pressure,
adding weight and complexity to spacecraft designs. Alternatives like krypton and argon are cheaper but offer lower
performance and pose integration difficulties in existing systems that are optimized for xenon.
Environmental adaptability is another major challenge. Systems like the MIT electro-aerodynamic aircraft are only
effective below altitudes of 2 kilometers, due to the significant drop in ionization efficiency at lower atmospheric
pressures. In contrast, traditional ion engines are designed to operate in high vacuum and cannot function effectively
in transitional pressure environments such as near-space or low-atmosphere zones. This creates a technological gap
between Earth-based and space-based ion propulsion capabilities.
Magnetic field precision is critical in systems like Hall effect thrusters. These rely on carefully tuned radial magnetic
fields to trap electrons and form stable plasmas. Slight deviations in the magnetic configuration can drastically affect
thrust efficiency. Furthermore, magnetic components are vulnerable to thermal saturation and demagnetization under
high operational temperatures, which can degrade performance over time or under continuous operation.
Another significant technical issue is ion beam divergence and recombination losses. Beams from ion engines typically
diverge by 10° to 30°, which causes a loss in axial thrust and raises the risk of contaminating nearby spacecraft surfaces.
The comparative field simulations shown in Fig. 5 and Fig. 6 illustrate how different electrode geometries can either
exacerbate or mitigate these losses, with open curved configurations (Fig. 6) showing superior ion guidance compared
to closed profiles (Fig. 5). Additionally, sheath instabilities near the extraction grids can lead to ion recombination,
reducing propulsion efficiency by as much as 15 to 25 percent.
Finally, ionic propulsion systems continue to struggle with low thrust-to-power ratios. Hall thrusters generally deliver
between 50 to 60 mN per kilowatt, a figure too low for missions requiring rapid acceleration or agile orbital maneuvers.
This limits their use to slow and gradual trajectory adjustments or deep space cruise operations rather than dynamic or
tactical applications.
2. Proposed methodology
The objective is to develop a modular, open-system ionic thruster that eliminates the reliance on magnetic field
guidance by instead engineering the topology of the negative electrode to control ion trajectories, minimize
recombination, and shape the electric field effectively. This concept leverages electrostatic-only field manipulation to
direct positive ions, reducing system complexity and thermal sensitivity associated with traditional magnetic
configurations.
[2]
The thruster architecture utilizes a corona wire or thin emitter as the positively charged ionization electrode, paired
with a negatively charged collector electrode whose curvature and edge geometry are carefully designed to steer
electric field lines. The optimized electrode configurations shown in Fig. 1 and Fig. 2 demonstrate how geometric
refinements can enhance ion flow direction and minimize energy losses. This method allows precise ion acceleration
in the desired direction, while avoiding the need for magnetic trapping or shielding mechanisms. Fig. 5 illustrates the
field confinement achievable with closed electrode geometries, while Fig. 6 demonstrates the enhanced ion throughput
possible with optimized open configurations.
[3]
By optimizing the electrode geometry, recombination zones and field
divergence are minimized, thus improving thrust efficiency and ensuring consistent particle ejection.
[4]
In contrast to enclosed thruster systems like Hall or gridded ion engines, this design adopts an open structural layout.
In atmospheric conditions, the open geometry naturally facilitates passive intake of ambient air via Bernoulli-driven
inflow. The air is ionized as it moves through the electric field region, enabling entrainment of neutral particles into
the ion stream and enhancing net thrust. This passive intake mechanism removes the need for auxiliary compressors
or pumps and is particularly well-suited for silent, low-maintenance operation in drone or UAV platforms.
[9]
Scalability is achieved through proportional extension of the electrode length. While the ion acceleration path (and
hence exhaust velocity) remains constant—being determined solely by the applied voltage—the total ionized mass
flow increases with surface area. This allows the thrust output to scale linearly without affecting the core propulsion
dynamics. Unlike conventional designs that suffer from nonlinear scaling inefficiencies at high input powers,
[3]
this
architecture maintains consistent performance across size classes.
The modular nature of this design further allows integration of multiple thruster units along the structural skin of a
vehicle or satellite. Each unit operates independently and can be selectively activated, enabling distributed thrust
vectoring, redundancy, and fault tolerance.
[10]
This is particularly advantageous for platforms requiring directional
control without mechanical actuators, and for spacecraft or drones operating in environments with limited access for
repair.
Fig. 4: First prototype testing of electrode modification.
Compared to magnetic and closed-chamber systems, the proposed approach reduces system mass, complexity, and
manufacturing costs. It eliminates the need for high-pressure gas storage, magnetic shielding, or grid alignment
tolerances found in traditional gridded ion thrusters.
[6]
The entire propulsion process—from ion generation to
acceleration—relies purely on electrostatics, making it ideal for low-power missions. This principle is validated
through the experimental prototype shown in Fig. 4, which demonstrates functional ion acceleration using minimal
infrastructure, making it ideal for low-power missions, particularly in micro-UAVs, nanosatellites, and experimental
solid-state aircraft. Furthermore, its dual-mode compatibility with both atmospheric and vacuum conditions increases
deployment versatility, potentially enabling multi-phase operation from launch to space transition.
[7]
3. Implementation
3.1 Stage 1: Electric field modeling
3.1.1 Electric field of a point charge
At a point r=(x,y) due to a charge q
i
at position r
i
=(x
i
,y
i
):
E
i
(r)=
1
4πε
0
q
i
(r-r
i
)
|r-r
i
|
3
(1)
where,
r=(x,y) is the observation point in 2D space,
r
i
=(x
i
,y
i
) is the position of the source charge q
i
,
ε
0
=8.854×10
-12
F/m is the vacuum permittivity,
E
i
is the electric field at r due to q
i
,
E
net
=
E
ii
is the net electric field from all point charges.
This formulation is fundamental for computing the superposed field distribution from discrete charges—essential in
understanding field shaping around electrodes. The practical applications of these calculations are demonstrated in
Fig. 5 and Fig. 6, which show how different electrode geometries produce distinct field patterns and ion trajectories.
3.1.2 Minimum radius of curvature
For a cylindrical conductor or electrode with radius of curvature r, the electric field at its surface due to a potential
difference V is approximately:
E=
V
rln
2h
r
(2)
where,
E is the electric field intensity at the conductor surface,
V is the potential difference between the electrode and its reference (e.g., ground),
r is the radius of curvature at the conductor tip,
h is the distance from the conductor to the ground plane or opposing electrode.
This relation provides a practical way to estimate field concentration at sharp points—critical for predicting corona
onset regions.
3.1.3 Simulation methodology
a) Initialize 2D Grid
Create a meshgrid of points over the defined range using:
X,Y=meshgrid(x,y) (3)
where,
x[x
min
,x
max
] and y[y
min
,y
max
] define the spatial simulation bounds,
X and Y represent the grid coordinates of each point in the 2D plane.
b) Initialize fields:
E
x
(x,y)=0, E
y
(x,y)=0 (4)
where,
E
x
and E
y
are the x and y components of the electric field at each grid point.
c) Loop over all charges
For each charge (x
i
,y
i
,q
i
):
Compute displacement:
dx=X-x
i
, dy=Y-y
i
(5)
where,
dx and dy are component-wise differences between grid points and the charge location.
Compute distance:
r
2
=dx
2
+dy
2
, r=
r
2
(6)
where,
r
2
is the squared distance from the charge to a grid point,
r is the Euclidean distance, used in field decay calculations.
Apply mask to avoid division by zero:
mask=r>ϵ (7)
where,
ϵ is a small positive constant to exclude singularities (e.g., 10
-6
m).
Compute field components (only where mask is True):
E
x
i
=kq
i
dx
r
3
, E
y
i
=kq
i
dy
r
3
(8)
where,
k=
1
4πε
0
is Coulomb’s constant,
q
i
is the charge value,
E
x
i
,E
y
i
are the field components at each point.
Accumulate:
E
x
+=E
x
i
, E
y
+=E
y
i
(9)
which adds the contribution of each charge to the total field.
d) Compute field magnitude:
E
magnitude
=
E
x
2
+E
y
2
(10)
where,
E
magnitude
is the scalar field strength at each grid point—useful for visualizing field peaks.
e) Normalize direction vectors (for uniform arrow length):
E
x_norm
=
E
x
E
magnitude
+δ
, E
y_norm
=
E
y
E
magnitude
+δ
(11)
where:
δ is a small stabilizer to avoid division by zero,
E
x_norm
,E
y_norm
are unit direction vectors for consistent arrow scaling.
f) Visualize the field:
Use quiver() or streamplot() to depict vector flow,
Color arrows using E
magnitude
for intensity—highlighting hotspots and field gradients.
g) Highlight critical areas:
Overlay points where:
E
magnitude
≥E
corona
(12)
where,
E
corona
is the minimum field strength required to trigger ionization (corona discharge).
These regions inform where geometric smoothing or material changes are necessary to avoid arcing.
3.2 Stage 2: Discharge physics
3.2.1 Breakdown voltage for townsend discharge
Townsend discharge defined as:
U
breakdown Townsend
=
dE
I
eλ
e
ln
d
λ
e
(13)
where,
U
breakdown Townsend
is the minimum voltage to initiate breakdown in gas via electron avalanche,
d is the inter-electrode gap distance (m),
E
I
is the ionization energy of the working gas (eV),
λ
e
is the electron mean free path in the gas (m),
e is Euler’s number (≈2.718), the base of natural logarithms.
This equation is vital for determining electrode spacing and applied voltage needed to initiate discharge reliably under
given atmospheric conditions. The experimental implementation shown in 3 validates these theoretical predictions,
demonstrating successful discharge initiation and measurable thrust generation.
L=
k
B
T
πr
I
2
(14)
where,
L is the mean free path of gas ions (m),
k
B
=1.38×10
-23
J/K is the Boltzmann constant,
T is the absolute temperature of the gas in Kelvin,
r
I
is the ionic radius of the gas molecule (m).
This relationship aids in selecting appropriate working gases and predicting discharge uniformity across operating
temperatures.
3.2.2 High voltage generation circuits
Two main circuit topologies were considered:
ZVS (Zero Voltage Switching) Circuit,
[11]
used for efficient low-noise voltage stepping without hard-switching losses.
Marx Generator,
[12]
used for generating high-voltage pulses by charging capacitors in parallel and discharging them in
series—suitable for impulse or burst-mode operations.
3.3 Stage 3: Material selection
3.3.1 Electrode materials
Aluminum is considered due to its relatively high electrical conductivity, approximately 3.5×10
7
S/m. However, it is
prone to oxidation, which reduces conductivity over time, especially in high-voltage environments. From a fabrication
standpoint, aluminum is easy to machine and can be cast or extruded into a variety of shapes. Nevertheless, the
formation of non-conductive aluminum oxide layers requires mechanical or chemical removal prior to deployment.
To mitigate this issue, surface treatments such as electroplating, anodizing, or the application of oxidation-resistant
coatings (e.g., silicone-based varnishes) are typically employed to preserve conductivity and protect against
environmental degradation.
3D printing emerges as an alternative method for producing custom electrode geometries. Conductive filaments,
including carbon-filled composites like graphene or carbon nanotubes, and metallic filaments such as stainless steel or
titanium, can be used to achieve acceptable levels of conductivity. This approach is especially advantageous when
complex geometries such as non-planar or hollow structures are needed, allowing the designer to tailor the electrode
profile to minimize ion wastage and optimize field shaping.
3.3.2 Surface conversion to conductive
To enhance the conductivity of base materials, electroplating is widely employed. Silver plating, with a typical
thickness of 5–10 µm, offers minimal resistance and remains stable under high-voltage conditions, making it suitable
for precision applications. Nickel plating is often chosen in harsher operational environments due to its superior
corrosion resistance and good electrical performance under high-voltage stress. Copper plating is more cost-effective
and readily available, making it suitable for low-to-medium power applications. However, copper is prone to oxidation
and may require additional protective coatings for long-term durability.
The electroplating procedure begins with surface preparation, typically involving solvent cleaning with agents such as
acetone to remove any oils, grease, or contaminants. An activation step follows, where a dilute acid like HCl is applied
to promote surface readiness for plating. The electrode is then immersed into a plating solution containing the desired
metal ions (e.g., copper, nickel, or silver), and a constant current density, typically ranging between 1–10 A/dm², is
applied. This ensures uniform deposition and strong adhesion of the plated layer to the substrate.
3.4 Stage 4: Electrode geometry optimization
3.4.1 Modeling the 3D Geometry to minimize ion wastage
The optimization of electrode geometry begins with simulation tools, particularly those based on the Finite Element
Method (FEM). Using solvers such as COMSOL Multiphysics, one can accurately simulate the electric field
distribution around the negative electrode. These simulations help to identify regions of field divergence where ion
trajectories may deviate from the intended direction. The electrode shape is then adjusted to minimize sharp edges and
maintain a concave profile that guides ions directly toward the positive electrode. This geometric refinement reduces
regions prone to unwanted corona discharge and enhances ion throughput.
In addition to initial simulations, FEM solvers are used to conduct Finite Element Analysis (FEA) for optimizing the
electric potential across the electrode surface. The primary objective is to eliminate localized electric field spikes,
which can result in ion wastage or unintended discharges. To accomplish this, the meshing density is increased in
regions exhibiting high electric field gradients while remaining coarse in areas of lower significance. This ensures
computational efficiency while preserving accuracy in critical zones. The comparative analysis between closed
electrode profiles (Fig. 5) and open curved configurations (Fig. 6) illustrates how simulation results directly inform
optimal geometry selection for maximum ion throughput.
Fig. 5: Point charge behaving with negative ellipse profile.
Fig. 6: Point charge behaving with two curved slabs.
3.4.2 Modular design for efficient ion flow
A modular approach to electrode geometry allows for easy adaptation and experimental testing. Modular sections
should be interchangeable, enabling the evaluation of different geometrical configurations such as cylindrical,
parabolic, or other custom shapes. These modules must include mounting mechanisms such as threaded inserts or
integrated joints to maintain structural integrity during operation. This modularity provides the flexibility to tune field
behavior and ion flow paths for maximum efficiency.
For thorough validation, each electrode module should include interchangeable side features to investigate ion losses
at the periphery. These features might include wing-like extensions, grooves, or tapered shapes designed to suppress
side ion escape. A dedicated swapping mechanism is recommended, ensuring that geometry changes can be
implemented without disturbing the alignment or configuration of the remaining system. This guarantees repeatability
and control over each test variable during experimental evaluations.
3.5 Stage 5: System integration
3.5.1 Skeletal hub design
The skeletal hub, acting as the structural backbone of the propulsion system, must be rigid, lightweight, and thermally
stable. Composite materials such as carbon-fiber-infused PLA, produced via 3D printing, offer an ideal balance of
strength and manufacturability. The hub should include provisions for adjustability, such as customizable slots and
mounting rails, allowing it to accommodate a variety of electrode modules and experimental setups.
Functionally, the hub must ensure precise mechanical alignment of the electrodes, preserving the optimal gap distance
required for efficient ion acceleration and uniform field distribution. It should incorporate features like adjustable
mounts, quick-release mechanisms for fast geometry changes, and reinforced channels for secure cable management.
These elements collectively contribute to the robustness and adaptability of the system.
3.5.2 Hub modularity and scalability
To enhance functionality, the hub should be designed with embedded slots and compartments for additional
components such as high-voltage power supplies, sensors for monitoring voltage, temperature, and ionization levels,
and passive or active capacitors for voltage regulation. Diagnostic tools like oscilloscopes and ammeters can also be
integrated within these provisions for real-time system monitoring.
Moreover, the hub should support rapid reconfiguration to test various electrode geometries or scale up the system. A
modular attachment system allows users to expand or adapt the architecture for different experimental regimes,
accommodating increased electrode counts, altered voltages, or alternative propulsion test parameters. This scalability
ensures the design remains applicable across both low-power micro-thrusters and larger, more demanding
configurations.
4. Results
Multiple experimental iterations were carried out to assess the viability, efficiency, and directional stability of the
proposed open-system ionic thruster. The initial prototype was tested with a basic electrode configuration and no
shielding or enclosure. During this test, the system produced approximately 2.35 mN of thrust, recorded as a 0.24 g
upward force on a precision scale, as seen in the experimental data in Fig. 3. This result verified initial ion acceleration
and directional ejection under laboratory conditions. Upon refining the electrode geometry, surface treatment, and
electrode alignment, a second iteration was developed, shown in Fig. 1 and Fig. 2. This improved setup demonstrated
an enhanced thrust output of up to 5 mN. The increase in performance can be attributed to reduced ion recombination
and more directed field lines due to geometric enhancements. However, as evident from field observation and mass
measurements, a significant portion of thrust was lost sideways. This loss primarily resulted from the absence of side
enclosures and electromagnetic shielding, which allowed the ion stream to diffuse laterally rather than remaining
collimated in the intended axial direction. Limitations in material availability restricted the achievable precision in
electrode shaping. Consequently, the optimized geometry was still sub-optimal in terms of beam guidance and thrust-
vector focus. Figs. 1 and 2 depict the final form of the iterated design, where improved shaping of the negative collector
helped confine ion trajectories, though further improvement is needed for ideal confinement. The effective range of
ion acceleration was also investigated. Ion diffusion was observed to dominate after approximately 40 cm–50 cm of
axial travel. Beyond this point, thrust efficiency dropped significantly, indicating the lack of beam confinement or
collimation—a problem that could be mitigated in future models by adding magnetic or electrostatic lensing. Fig. 4
presents the first electrode modification test, showcasing the early design phase that informed the more efficient
iterated models.
As in the basic simulation results it’s evident that the ion thruster provides more thrust with converging or diverging
tubes Fig. 6 rather than closed structures Fig. 5 and also diffuses more and has field losses more in open structures
(Fig. 6).
5. Conclusion
The development of the open-system ionic thruster presented in this work demonstrates a promising advancement
toward silent, efficient, and mechanically minimal propulsion under atmospheric conditions. By emphasizing the
shaping of the negative collector electrode to control electric field topology, the system eliminates the need for
magnetic confinement while maintaining directional ion acceleration. Experimental iterations confirmed thrust
generation up to 5 mN, validating the viability of electrostatic-only ion propulsion using ambient air as the working
medium. The observed lateral ion losses and limited confinement beyond 50 cm indicate the need for improvements
in plume collimation and side shielding, which form the basis for future refinements.
The modular and scalable nature of the design—achieved without moving parts—offers significant potential for
integration into low-noise aerial platforms such as UAVs, stealth drones, and high-altitude vehicles. Furthermore, the
ease of adapting electrode geometries and power supply configurations opens avenues for tailoring performance to
mission-specific requirements. Future work will focus on addressing observed limitations by incorporating side
enclosures, refining electrode fabrication with better materials, and enhancing power electronics. With further
optimization and system integration, this technology could contribute meaningfully to the advancement of next-
generation aerospace propulsion systems.
Conflict of Interest
There is no conflict of interest.
Supporting Information
Not applicable.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation
The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing
or editing of the manuscript and no images were manipulated using AI.
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