From the Writings of the Ari; translation and commentary by Baruch Emanuel Erdstein

In the following meditation, the Ari introduces us to the mystical methods by which, in the merit of Chanukah, we draw down sublime holiness to lower realms rarely privy to such lofty divine light.  Rebbe Nachman of Breslev teaches that the holiday of Chanukah, whose name is rooted in the Hebrew word "chinuch", meaning "education" or "becoming accustomed", guides us in our constant struggle with the forces attempting to distance us from G-d - those of the power of impure imagination, or in Hebrew "m'damei"; by purifying our imaginative capabilities we are able to break the primary force behind all our negative qualities and illusions.(Likutei Halachot, hilchot Chanukah 1:1)

The word "m'damei", whose numerical value (89) equals that of the word "Chanukah", is rooted in the letters dalet and mem, which spell the Hebrew word for "blood". Blood represents the negative powers of judgment, our mission it is to sweeten. Via the 44 (the numerical value of dalet, 4, and mem, 40) lights we kindle throughout Chanukah (including the shammas) and the awakening of consciousness they embody, the kelipot become nullified before us. ^[1] As we witness so clearly in our times, all that seems to stand between our present situation and complete national redemption is our resolve and clarity of our national will. In light of these insights, Chanukah, in which we celebrate our redemption from foreign powers which attempt to delude us into abandoning our G-d and His  Torah, is a particularly auspicious time for meditation, especially on the lights and lamps of the Chanukah menora.

The mystical meditations one should have for the lighting of the [Chanukah] lights primarily revolve around one supernal and complete mystical unification called "Ner" [Hebrew for "candle"]....Briefly, there are three primary aspects of the unification of  Zeir Anpin and  Nukva:  Havayah [united] with Eh-yeh (which has a numerical value of 47), Havayah with  Elo-him (equaling 112), and Havayah with Ado-nai (equaling 91). Sometimes one aspect becomes united, sometimes two, and sometimes all three, in which the above become completely unified - and [then] Nukva is called "Ner" [whose numerical value is 250], equaling the total of the above six divine names.

Havayah = 26 Eh-yeh = 21 Havayah = 26 Elo-him = 86 Havayah = 26 Ado-nai = 65 Plus 6, one for each name, the kolel, = "Ner" (250), spelled nun (50), reish (200)

In the first blessing ["...Who has commanded us to light the Chanukah candle"], all three [above unifications] are hinted at [in the word "candle"].

In the second blessing ["...Who created miracles..."], the second unification is hinted at.

And in the third blessing ["...Who has given us life..."], the lowest of all is hinted at.

" During the holiday, the loftiest of supernal levels of holiness are actually accessible even in the lowest of realms..."

I [Rabbi  Chaim Vital] have found in another manuscript that the first name Havayah (the one unified with Eh-yeh) should be  Ab [72], spelled out with  yuds, the second Havayah (the one unified with Elo-him) should be that of SaG [63], and the third Havayah (the one unified with Ado-nai) should be that of MaH [spelled out with alefs, 45]. One should meditate on these three [ways of spelling out the name] Havayah when one says the word "l'hadleek" [meaning "to light", in the first blessing], which has the numerical value of these three names,  Av, SaG, Mah.

Av = 72 SaG = 63 Mah = 45 Plus 1 for the kolel = "l'hadleek" (180), spelled lamed (30), hei (5), dalet (4), lamed (30), yud (10), kuf (100) plus the kolel.

[Also,] if one spells out the name Eh-yeh in the above meditation with yuds, equaling 161, uniting it with the Havayah spelled with yuds, equaling 72, one gets the numerical value of the word "regel" [Hebrew for "foot", equaling 233]. This hints at the fact that Chanukah is called a "pilgrimage festival" [in Hebrew, "regel", literally meaning "foot"], among the other holidays, as is mentioned in the handwritten notes in the introduction to the Tikunei  Zohar [even though it is not literally one of the three primary pilgrimage festivals]....This is the secret of the concept that the optimal time to light one's Chanukah menora is "until feet [literally 'foot', 'regel'] cease in the marketplace"...

The commandment to publicize the miracle of Chanukah demands that we light our menoras in a place visible to passers-by and at a time not so late that no one will be found in the streets to see them. The above term hints that the power of Chanukah is so great that, during the holiday, the loftiest of supernal levels of holiness (represented by the above unification of divine names, the "foot" - or "regel") are actually accessible even in the lowest of realms. These less than lofty dominions are represented by the term "marketplace" (in Hebrew, "shuk", related to the word for "thigh", associated with the  sefira of  hod, the eighth sefira from above), a place characterized by diffusion, disharmony, and susceptibility to the External Forces. (Ibid. 2:6, 3:1)  Chanuka shows us that sparks of holiness are everywhere and gives us the ability to redeem them, shining holy light even in realms of darkness.

" During the blessing ...one should meditate on the supernal River..."

One should meditate on the idea that the initials of the words "...to light the Chanukah candle" [in Hebrew, "l'hadleek ner Chanukah", in the first blessing] are the holy name called "Nachal" [meaning "stream" or "river"], which emanates from the initials of the words "He preserves kindness for two-thousand [years]" [in Hebrew, "notzer chesed l'alefim", the eighth and ninth of the Thirteen Attributes of Divine Mercy], as is known. The significance of this is [to show] that light [i.e. divine sustenance] is transmitted from supernal  Imma to Zeir Anpin, in order that he have enough strength to connect with the three above unifications, those of the Candle Meditation.

Generally speaking, once access to the sefira of  bina, the eighth sefira when counting from below and the lowest of the  sefirot associated with the "head" ( keter,  chochma, bina) has been achieved, so too are the remainder of the supernal sefirot of the "head" accessible. In the same way, the eighth of the  Thirteen Attributes of Mercy, that of "Notzer Chesed", grants access to the totality of the thirteen. The eight-branched Chanuka menora as well as the eight days of the Chanukah festival hint at this deep secret.

Thus, [during the blessing "...to light the Chanukah candle"] one should meditate on the supernal River [in Hebrew, "nachal", the initials of the blessing "l'hadleek ner Chanukah"], that it is the spelling-out of the name Havayah with alefs [known as "Mah"] - with the letter alef of the spelling out of the letter  vav transformed into the name Eh-yeh expanded [in  Ribua], like this:

Yud, vav, dalet Hei, alef Vav - alef, alef-hei, alef-hei-yud, alef-hei-yud-hei - vav Hei, alef

This name [which has the same numerical value as "nachal", "river", 88, indicates the concept of Imma, which "shines" [her light] unto Zeir Anpin as she is enclothed within him...

After, in the word "Chanukah" [again, within the first blessing] have in mind that in the same way that [via our meditations] we drew divine sustenance from Imma to Zeir Anpin with the River Meditation [above] in order that they (ed. likely Zeir Anpin and Nukva) unite via the three unifications, known as the Candle Meditation - so too, now we [utilize] the name  Sag [Havayah spelled-out to equal 63], of Imma, whose numerical value plus the simple value of the name Havayah (26) adds up to 26 plus 63, the same as the numerical value of the word "Chanukah" [plus the kolel: 89].

Here, "Chanukah" is spelled: chet (8), nun (50), vav (6), chaf (20), hei (5), totaling 89, which is also the same as "nachal", the "River" mentioned above.

This [time, via the meditation] we are drawing divine sustenance in Nukva, which [itself] is called "Candle" [or "Ner"], and thus we arrive at the "Chanukah candle" ["Ner Chanukah" of the blessing].

Also, on the word "Chanukah", one should meditate upon what the Sages taught that it is made up of the words "chanu-" [meaning "encamped" or "rested"] and "-ka" [spelled chaf, hei, the numerical of 25], which is the secret of the 25 letters of the six names that a person should concentrate on in the Candle Meditation.

The Zohar ( Tikunei Zohar, 13) teaches that these 25 letters are also the secret of the 25 letters of the verse "Hear, O' Israel, the Lord is our G-d, the Lord is One." (Deut. 6:4) [Shaar HaKavanot, Inyan Chanukah]