ISO 11221:2011 宇宙システム—宇宙ソーラーパネル—宇宙船の充電による静電放電試験方法 | ページ 4

2.1

active gap

gap between solar cells across which a potential difference is present when the solar array power is available

2.2

blow-off

emission of negative charges into space due to an electrostatic discharge

2.3

collisionless plasma

plasma in which the mean free paths of electron-neutral, ion-neutral and coulomb collisions are longer than the scale length of interest

Note 1 to entry: Chamber length is an example of a scale length of interest.

2.4

differential charging

spacecraft charging where any two points are charged to different potentials

2.5

differential capacitance

capacitance between any two points in a spacecraft, especially between the insulator surface and the spacecraft body

2.6

differential voltage

potential difference between any two points in a spacecraft during spacecraft charging, especially between the insulator exterior surface potential and the spacecraft chassis potential

2.7

discharge inception voltage

lowest voltage at which discharges of specified magnitude will recur when a DC voltage is applied between any two points in a spacecraft, especially between the insulator surface and the spacecraft body

2.8

electrical breakdown

failure of the insulation properties of a dielectric, resulting in a sudden release of charge with possible damage to the dielectric concerned

2.9

electric propulsion

spacecraft propulsion system in which the thrust is generated by accelerating charged particles that are neutralized before they are ejected in order to produce a jet

2.10

electrostatic discharge

electrical breakdown of dielectric or gas or vacuum gaps, and also of surface interface of dissimilar materials, caused by differential charging of parts of dielectric materials and their interfaces

2.11

gap distance

distance between biased cells or conductors

2.12

glow discharge

gaseous discharge with a surface glow near the cathode surface

Note 1 to entry: The origin of the ionized gas is mostly ambient neutral gas molecules rather than metal vapour from the cathode surface.

2.13

inverted potential gradient

result of differential charging where the insulating surface or dielectric reaches a positive potential with respect to the neighbouring conducting surface or metal

Note 1 to entry: This phenomenon is also known as PDNM (positive dielectric negative metal).

2.14

non-sustained arc

passage of current from an external source through a conductive path that lasts only while the primary discharge current flows

2.15

normal potential gradient

result of differential charging where the insulating surface or dielectric reaches a negative potential with respect to the neighbouring conducting surface or metal

Note 1 to entry: This phenomenon is also known as NDPM (negative dielectric positive metal).

2.16

permanent sustained arc

passage of current from an external source through a conductive path that keeps flowing until the external source is intentionally shut down

Note 1 to entry: Some permanent sustained arcs may leave a permanent conductive path even after the shut-down.

2.17

Poisson process

stochastic process in which events occur independently of one another

2.18

power generation voltage

potential difference between the positive and negative terminals of a solar array string

2.19

primary arc

trigger arc

developed phase of a primary discharge, under an inverted potential gradient, which is associated with cathodic spot formation at a metallic or semiconductor surface

2.20

primary discharge

initial electrostatic discharge which, by creating a conductive path, can trigger a secondary arc

Note 1 to entry: The current can include blow-off current and surface flashover current.

2.21

punch-through

dielectric breakdown between two sides of an insulator material

2.22

ram

space in front of and adjacent to a spacecraft in which the plasma density can be enhanced by the motion of the spacecraft

2.23

satellite capacitance

absolute capacitance

capacitance between a satellite body and the ambient plasma

2.24

secondary arc

passage of current from an external source, such as a solar array, through a conductive path initially generated by a primary discharge

Note 1 to entry: Figure 1 shows the various stages of a secondary arc.

2.25

snapover

phenomenon caused by secondary electron emission that can lead to electron collection on insulating surfaces in an electric field

2.26

solar array front surface

solar array surface where solar cells are laid down

Note 1 to entry: Solar cells are laid down on the side of a solar panel that normally faces the sun.

2.27

solar array back surface

solar array surface where solar cells are not laid down

Note 1 to entry: Solar cells are not laid down on the side of a solar panel that normally faces away from the sun.

2.28

surface charging

deposition of electrical charges onto, or their removal from, external surfaces

2.29

surface flashover

surface discharge propagating laterally over a dielectric material

Note 1 to entry: Surface flashover is sometimes called a “brushfire discharge”.

2.30

temporary sustained arc

passage of current from an external source through a conductive path that lasts longer than a primary discharge current pulse but terminates without leaving a permanent conductive path

2.31

wake