Hall effect thruster
View Patent ↗A Hall effect thruster including a downstream end of its annular channel presenting a cross-section that is variable to vary a thrust and a specific impulse of the thruster.
1. A Hall effect thruster comprising:
an annular channel defined by an inner wall and an outer wall, wherein the inner wall and the outer wall are coaxial about a central axis, the annular channel having a downstream end that is open and an upstream end that is closed, and the inner wall being movable in an axial direction and having a diameter that decreases in a downstream direction;
an actuator for moving the inner wall in the axial direction;
an electric circuit including an anode situated at the upstream end, a cathode at the downstream end, and an electric voltage source configured to supply a voltage between the anode and cathode;
an injection circuit for injecting a mass flow of propulsion gas into the annular channel;
a magnetic circuit for generating a magnetic field at the downstream end; and
a control unit that is connected to the electric circuit, to the injection circuit, and to the actuator, and that is configured to vary the mass flow and/or the voltage and to regulate an axial position of the inner wall relative to the outer wall as a function of the mass flow and/or of the voltage to adapt a cross-section of the downstream end to maintain a plasma density at the downstream end.
2. The Hall effect thruster according to claim 1 , wherein the actuator is a piezoelectric actuator.
3. The Hall effect thruster according to claim 2 , wherein the piezoelectric actuator is an ultrasonic motor.
4. The Hall effect thruster according to claim 1 , wherein the inner wall and the outer wall are made of ceramic material.
5. A Hall effect thruster comprising:
an annular channel defined by an inner wall and an outer wall, wherein the inner wall and the outer wall are coaxial about a central axis, the annular channel having a downstream end that is open and an upstream end that is closed, and the outer wall being movable in an axial direction and having a diameter that increases in a downstream direction;
an actuator for moving the outer wall in the axial direction; an electric circuit including an anode situated at the upstream end, a cathode at the downstream end, and an electric voltage source configured to establish a voltage between the anode and cathode;
an injection circuit for injecting a mass flow of propulsion gas into the annular channel; a magnetic circuit for generating a magnetic field at the downstream end; and
a control unit that is connected to the electric circuit, to the injection circuit, and to the actuator, and configured to vary the mass flow and/or the voltage and to regulate an axial position of the outer wall relative to the inner wall to adapt a cross-section of the downstream end as a function of the mass flow and/or of the voltage to maintain a plasma density at the downstream end.
6. The Hall effect thruster according to claim 5 , wherein the actuator is a piezoelectric actuator.
7. The Hall effect thruster according to claim 6 , wherein the piezoelectric actuator is an ultrasonic motor.
8. The Hall effect thruster according to claim 5 , wherein the inner wall and the outer wall are made of ceramic material.
9. A space vehicle including at least one Hall effect thruster comprising:
an annular channel defined by an inner wall and an outer wall, wherein the inner wall and the outer wall are coaxial about a central axis, the annular channel having a downstream end that is open and an upstream end that is closed, and the inner wall being movable in an axial direction and having a diameter that decreases in a downstream direction;
an actuator for moving the inner wall in the axial direction;
an electric circuit including an anode situated at the upstream end, a cathode at the downstream end, and an electric voltage source configured to establish a voltage between the anode and cathode;
an injection circuit for injecting a mass flow of propulsion gas into the annular channel; a magnetic circuit for generating a magnetic field at the downstream end; and
a control unit that is connected to the electric circuit, to the injection circuit, and to the actuator, and that is configured to vary the mass flow and/or the voltage and to regulate an axial position of the inner wall relative to the outer wall as a function of the mass flow and/or of the voltage to adapt a cross-section of the downstream end to maintain a plasma density at the downstream end.
10. A method of regulating a Hall effect thruster comprising:
an annular channel defined by an inner wall and an outer wall, wherein the inner wall and the outer wall are coaxial about a central axis, the annular channel having a downstream end that is open and an upstream end that is closed, and the inner wall being movable in an axial direction and having a diameter that decreases in a downstream direction;
an actuator for moving the inner wall in the axial direction;
an electric circuit including an anode situated at the upstream end, a cathode at the downstream end, and an electric voltage source configured to establish a voltage between the anode and cathode;
an injection circuit for injecting a mass flow of propulsion gas into the annular channel;
a magnetic circuit for generating a magnetic field at the downstream end; and
a control unit that is connected to the electric circuit, to the injection circuit, and to the actuator, wherein: the mass flow and/or the voltage changes as a function of a target thrust; and
an axial position of the inner wall is modified relative to the outer wall to adapt a cross-section of the downstream end as a function of the mass flow and/or of the voltage to maintain a plasma density at the downstream end.
11. A space vehicle including at least one Hall effect thruster comprising:
an annular channel defined by an inner wall and an outer wall, wherein the inner wall and the outer wall are coaxial about a central axis, the annular channel having a downstream end that is open and an upstream end that is closed, and the outer wall being movable in an axial direction and having a diameter that increases in a downstream direction;
an actuator for moving the outer wall in the axial direction;
an electric circuit including an anode situated at the upstream end, a cathode at the downstream end, and an electric voltage source configured to establish a voltage between the anode and cathode;
an injection circuit for injecting a mass flow of propulsion gas into the annular channel;
a magnetic circuit for generating a magnetic field at the downstream end; and
a control unit that is connected to the electric circuit, to the injection circuit, and to the actuator, and that is configured to vary the mass flow and/or the voltage and to regulate an axial position of the outer wall relative to the inner wall as a function of the mass flow and/or of the voltage to adapt a cross-section of the downstream end to maintain a plasma density at the downstream end.
12. A method of regulating a Hall effect thruster comprising:
an annular channel defined by an inner wall and an outer wall, wherein the inner wall and the outer wall are coaxial about a central axis, the annular channel presenting a downstream end that is open and an upstream end that is closed, and the outer wall being movable in an axial direction and presenting a diameter that increases in a downstream direction;
an actuator for moving the outer wall in the axial direction;
an electric circuit including an anode situated at the upstream end, a cathode at the downstream end, and an electric voltage source configured to establish a voltage between the anode and cathode;
an injection circuit for injecting a mass flow of propulsion gas into the annular channel;
a magnetic circuit for generating a magnetic field at the downstream end; and
a control unit that is connected to the electric circuit, to the injection circuit, and to the actuator;
wherein: the mass flow and/or the voltage changes as a function of a target thrust; and
an axial position of the outer wall is modified relative to the inner wall to adapt a cross-section of the downstream end as a function of the mass flow and/or of the voltage to maintain a plasma density at the downstream end.